diff --git a/Makefile b/Makefile
index e1ceb59ca3..b96a03aec4 100644
--- a/Makefile
+++ b/Makefile
@@ -20,11 +20,13 @@ LIBTIRPC_STAMP := $(APPS_BUILD)/.stamp_libtirpc
 GNULIB_STAMP   := $(APPS_BUILD)/.stamp_gnulib
 ZLIB_STAMP     := $(APPS_BUILD)/.stamp_zlib
 OPENSSL_STAMP  := $(APPS_BUILD)/.stamp_openssl
+LIBCXX_STAMP   := $(APPS_BUILD)/.stamp_libcxx
 MERGE_BASE_STAMP    := $(APPS_BUILD)/.stamp_merge_base_sysroot
 MERGE_TIRPC_STAMP   := $(APPS_BUILD)/.stamp_merge_tirpc
 MERGE_GNULIB_STAMP  := $(APPS_BUILD)/.stamp_merge_gnulib
 MERGE_ZLIB_STAMP    := $(APPS_BUILD)/.stamp_merge_zlib
 MERGE_OPENSSL_STAMP := $(APPS_BUILD)/.stamp_merge_openssl
+MERGE_LIBCXX_STAMP  := $(APPS_BUILD)/.stamp_merge_libcxx
 MERGE_ALL_STAMP     := $(APPS_BUILD)/.stamp_merge_sysroot
 
 TOOL_ENV       := $(APPS_BUILD)/.toolchain.env
@@ -41,7 +43,7 @@ TESTABLE_APPS  := bash coreutils curl git grep lmbench sed tinycc
 APP            ?= $(TESTABLE_APPS)
 
 # -------- Phonies -------------------------------------------------------------
-.PHONY: all preflight dirs print-config check-build libtirpc gnulib zlib openssl merge-base-sysroot merge-sysroot lmbench bash nginx coreutils cpython git curl grep sed postgres clean clean-all rebuild-libs rebuild-sysroot install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install
+.PHONY: all preflight dirs print-config check-build libtirpc gnulib zlib openssl libcxx merge-base-sysroot merge-sysroot lmbench bash nginx coreutils cpython git curl grep sed gcc binutils postgres clean clean-all rebuild-libs rebuild-sysroot install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install-gcc install-binutils install
 
 all: preflight libtirpc gnulib merge-sysroot lmbench bash
 
@@ -144,6 +146,14 @@ $(OPENSSL_STAMP): $(APPS_ROOT)/openssl/compile_openssl.sh | $(TOOL_ENV)
 
 openssl: $(OPENSSL_STAMP)
 
+# ---------------- libc++ (via compile_libcxx.sh) ------------------------------
+$(LIBCXX_STAMP): $(APPS_ROOT)/llvm-project/compile_libcxx.sh | $(TOOL_ENV)
+	. '$(TOOL_ENV)'
+	JOBS='$(JOBS)' '$(APPS_ROOT)/llvm-project/compile_libcxx.sh'
+	touch '$@'
+
+libcxx: $(LIBCXX_STAMP)
+
 # ---------------- Merge sysroot + overlay -------------------------------------
 $(MERGE_BASE_STAMP): | $(TOOL_ENV)
 	@echo "[merge] refreshing base merged sysroot"
@@ -194,7 +204,16 @@ $(MERGE_OPENSSL_STAMP): $(MERGE_BASE_STAMP) $(OPENSSL_STAMP)
 	touch '$@'
 
 
-$(MERGE_ALL_STAMP): $(MERGE_TIRPC_STAMP) $(MERGE_GNULIB_STAMP) $(MERGE_ZLIB_STAMP) $(MERGE_OPENSSL_STAMP)
+$(MERGE_LIBCXX_STAMP): $(MERGE_BASE_STAMP) $(LIBCXX_STAMP)
+	# libc++ headers (into include/wasm32-wasi/c++/ so clang's -isystem finds them)
+	mkdir -p '$(MERGED_SYSROOT)/include/wasm32-wasi/c++'
+	rsync -a '$(APPS_OVERLAY)/usr/include/c++/' '$(MERGED_SYSROOT)/include/wasm32-wasi/c++/' || true
+	rsync -a '$(APPS_OVERLAY)/usr/lib/wasm32-wasi/' '$(MERGED_SYSROOT)/lib/wasm32-wasi/' || true
+	rsync -a '$(APPS_OVERLAY)/lib/wasm32-wasi/'     '$(MERGED_SYSROOT)/lib/wasm32-wasi/' || true
+	touch '$@'
+
+
+$(MERGE_ALL_STAMP): $(MERGE_TIRPC_STAMP) $(MERGE_GNULIB_STAMP) $(MERGE_ZLIB_STAMP) $(MERGE_OPENSSL_STAMP) $(MERGE_LIBCXX_STAMP)
 	touch '$@'
 
 merge-sysroot: $(MERGE_ALL_STAMP)
@@ -259,12 +278,27 @@ sed: $(MERGE_BASE_STAMP)
 	. '$(TOOL_ENV)'
 	JOBS='$(JOBS)' '$(APPS_ROOT)/sed/compile_sed.sh'
 
+# ---------------- gcc (WASM build) --------------------------------------------
+# Uses gcc/compile_gcc.sh to cross-compile GCC cc1 as a wasm32-wasi binary.
+# Requires libc++ in the merged sysroot (for compiling GCC's C++ source).
+# Stages artifacts under build/gcc/usr/local/bin.
+gcc: $(MERGE_LIBCXX_STAMP)
+	. '$(TOOL_ENV)'
+	JOBS='$(JOBS)' '$(APPS_ROOT)/gcc/compile_gcc.sh'
+
+# ---------------- binutils (WASM build) ----------------------------------------
+# Uses binutils/compile_binutils.sh to cross-compile ld and as as wasm32-wasi
+# binaries.  Pure C — no libc++ needed.  Stages to build/binutils/usr/local/bin.
+binutils: $(MERGE_ZLIB_STAMP)
+	. '$(TOOL_ENV)'
+	JOBS='$(JOBS)' '$(APPS_ROOT)/binutils/compile_binutils.sh'
+
 rebuild-libs:
-	rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)' \
-	  '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_ALL_STAMP)'
+	rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)' '$(LIBCXX_STAMP)' \
+	  '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_LIBCXX_STAMP)' '$(MERGE_ALL_STAMP)'
 
 rebuild-sysroot:
-	rm -f '$(MERGE_BASE_STAMP)' '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_ALL_STAMP)'
+	rm -f '$(MERGE_BASE_STAMP)' '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_LIBCXX_STAMP)' '$(MERGE_ALL_STAMP)'
 
 # ---------------- cpython (WASM build) ----------------------------------------
 # Placeholder target to preserve the per-app staging/layering pattern.
@@ -300,7 +334,13 @@ install-lmbench:
 install-coreutils:
 	'$(APPS_ROOT)/scripts/post_install.sh' '$(LINDFS_ROOT)' '$(APPS_BUILD)' coreutils
 
-install: install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils
+install-gcc:
+	'$(APPS_ROOT)/scripts/post_install.sh' '$(LINDFS_ROOT)' '$(APPS_BUILD)' gcc
+
+install-binutils:
+	'$(APPS_ROOT)/scripts/post_install.sh' '$(LINDFS_ROOT)' '$(APPS_BUILD)' binutils
+
+install: install-bash install-nginx install-git install-curl install-grep install-sed install-lmbench install-coreutils install-gcc install-binutils
 
 clean:
 	$(MAKE) -C '$(APPS_ROOT)/lmbench/src' clean || true
@@ -309,6 +349,9 @@ clean:
 	-rm -rf '$(APPS_BIN_DIR)/nginx'
 	-$(MAKE) -C '$(APPS_ROOT)/nginx' clean || true
 	-rm -rf '$(APPS_OVERLAY)' '$(MERGED_SYSROOT)' '$(APPS_BIN_DIR)' '$(APPS_LIB_DIR)' '$(TOOL_ENV)'
-	-rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)'
-	-rm -f '$(MERGE_BASE_STAMP)' '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_ALL_STAMP)'
+	'$(APPS_ROOT)/gcc/clean.sh'
+	'$(APPS_ROOT)/binutils/clean.sh'
+	'$(APPS_ROOT)/llvm-project/clean.sh'
+	-rm -f '$(LIBTIRPC_STAMP)' '$(GNULIB_STAMP)' '$(ZLIB_STAMP)' '$(OPENSSL_STAMP)' '$(LIBCXX_STAMP)'
+	-rm -f '$(MERGE_BASE_STAMP)' '$(MERGE_TIRPC_STAMP)' '$(MERGE_GNULIB_STAMP)' '$(MERGE_ZLIB_STAMP)' '$(MERGE_OPENSSL_STAMP)' '$(MERGE_LIBCXX_STAMP)' '$(MERGE_ALL_STAMP)'
 	$(MAKE) -C '$(APPS_ROOT)/libtirpc' distclean || true
diff --git a/binutils/clean.sh b/binutils/clean.sh
new file mode 100755
index 0000000000..af4e361610
--- /dev/null
+++ b/binutils/clean.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+APPS_BUILD="$APPS_ROOT/build"
+
+rm -rf "$APPS_BUILD/binutils-build"
+rm -rf "$APPS_BUILD/binutils"
+rm -f "$SCRIPT_DIR/ld.wasm" "$SCRIPT_DIR/ld.opt.wasm" "$SCRIPT_DIR/ld.opt.cwasm"
+rm -f "$SCRIPT_DIR/as.wasm" "$SCRIPT_DIR/as.opt.wasm" "$SCRIPT_DIR/as.opt.cwasm"
diff --git a/binutils/compile_binutils.sh b/binutils/compile_binutils.sh
new file mode 100755
index 0000000000..984d9d1477
--- /dev/null
+++ b/binutils/compile_binutils.sh
@@ -0,0 +1,224 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+###############################################################################
+# Binutils WASI build helper for lind-wasm-apps
+#
+# Cross-compiles GNU Binutils 2.46.0 (ld, as) to wasm32-wasi so that the
+# linker and assembler can run inside the Lind sandbox alongside cc1 from GCC.
+# The resulting tools target x86_64-linux-gnu (matching GCC's --target).
+#
+# High-level strategy:
+#   1. Out-of-tree build
+#   2. Configure with --host=wasm32-unknown-wasi, --target=x86_64-linux-gnu
+#      Generator tools are built natively via CC_FOR_BUILD; ld/as are cross-
+#      compiled to wasm32 via CC.
+#   3. Build with 'make all-ld all-gas' (linker + assembler only)
+#   4. Stage ld and as, post-process with wasm-opt + lind-boot
+#
+# Prerequisites:
+#   - Run 'make preflight merge-sysroot' first
+#   - Native gcc must be on PATH (for CC_FOR_BUILD)
+###############################################################################
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+BINUTILS_SRC="$APPS_ROOT/binutils"
+
+APPS_BUILD="$APPS_ROOT/build"
+MERGED_SYSROOT="$APPS_BUILD/sysroot_merged"
+STAGE_DIR="$APPS_BUILD/binutils/usr/local/bin"
+TOOL_ENV="$APPS_BUILD/.toolchain.env"
+
+if [[ -z "${LIND_WASM_ROOT:-}" ]]; then
+  LIND_WASM_ROOT="$(cd "$APPS_ROOT/.." && pwd)"
+fi
+
+WASM_OPT="${WASM_OPT:-$LIND_WASM_ROOT/tools/binaryen/bin/wasm-opt}"
+LIND_BOOT="${LIND_BOOT:-$LIND_WASM_ROOT/build/lind-boot}"
+
+JOBS="${JOBS:-$(nproc 2>/dev/null || getconf _NPROCESSORS_ONLN || echo 4)}"
+
+# ----------------------------------------------------------------------
+# 1) Load toolchain from Makefile preflight
+# ----------------------------------------------------------------------
+if [[ -r "$TOOL_ENV" ]]; then
+  # shellcheck disable=SC1090
+  . "$TOOL_ENV"
+else
+  echo "[binutils] ERROR: missing toolchain env '$TOOL_ENV' (run 'make preflight' first)" >&2
+  exit 1
+fi
+
+: "${CLANG:?missing CLANG in $TOOL_ENV}"
+: "${AR:?missing AR in $TOOL_ENV}"
+: "${RANLIB:?missing RANLIB in $TOOL_ENV}"
+: "${NM:?missing NM in $TOOL_ENV}"
+
+# Sanity checks
+if [[ ! -d "$BINUTILS_SRC" ]]; then
+  echo "[binutils] ERROR: source dir not found at '$BINUTILS_SRC'" >&2
+  exit 1
+fi
+if [[ ! -d "$MERGED_SYSROOT" ]]; then
+  echo "[binutils] ERROR: merged sysroot '$MERGED_SYSROOT' not found. Run 'make merge-sysroot' first." >&2
+  exit 1
+fi
+if ! command -v gcc &>/dev/null; then
+  echo "[binutils] ERROR: native gcc required for CC_FOR_BUILD but not found on PATH" >&2
+  exit 1
+fi
+
+mkdir -p "$STAGE_DIR"
+
+# ----------------------------------------------------------------------
+# 2) WASM toolchain flags
+# ----------------------------------------------------------------------
+CC_WASM="$CLANG --target=wasm32-unknown-wasi --sysroot=$MERGED_SYSROOT \
+  -pthread -matomics -mbulk-memory \
+  -I$MERGED_SYSROOT/include -I$MERGED_SYSROOT/include/wasm32-wasi"
+
+CFLAGS_WASM="-Os"
+
+LDFLAGS_WASM="-Wl,--import-memory,--export-memory,--max-memory=67108864 \
+  -Wl,--export=__stack_pointer,--export=__stack_low \
+  -L$MERGED_SYSROOT/lib/wasm32-wasi \
+  -L$MERGED_SYSROOT/usr/lib/wasm32-wasi"
+
+echo "[binutils] using CLANG          = $CLANG"
+echo "[binutils] using AR             = $AR"
+echo "[binutils] LIND_WASM_ROOT       = $LIND_WASM_ROOT"
+echo "[binutils] merged sysroot       = $MERGED_SYSROOT"
+echo "[binutils] stage dir            = $STAGE_DIR"
+echo "[binutils] CC_WASM              = $CC_WASM"
+echo
+
+# ----------------------------------------------------------------------
+# 3) Out-of-tree build directory
+# ----------------------------------------------------------------------
+BINUTILS_BUILD="$APPS_BUILD/binutils-build"
+mkdir -p "$BINUTILS_BUILD"
+
+echo "[binutils] build dir = $BINUTILS_BUILD"
+
+# ----------------------------------------------------------------------
+# 4) Configure
+# ----------------------------------------------------------------------
+BUILD_TRIPLET="$(gcc -dumpmachine 2>/dev/null || echo x86_64-linux-gnu)"
+
+echo "[binutils] configuring…"
+echo "[binutils]   --build=$BUILD_TRIPLET"
+echo "[binutils]   --host=wasm32-unknown-wasi"
+echo "[binutils]   --target=x86_64-linux-gnu"
+
+pushd "$BINUTILS_BUILD" >/dev/null
+
+"$BINUTILS_SRC/configure" \
+  --build="$BUILD_TRIPLET" \
+  --host=wasm32-unknown-wasi \
+  --target=x86_64-linux-gnu \
+  --disable-shared \
+  --enable-static \
+  --disable-nls \
+  --disable-plugins \
+  --disable-gdb \
+  --disable-gdbserver \
+  --disable-gprofng \
+  --disable-sim \
+  --disable-gold \
+  --enable-ld=yes \
+  --disable-werror \
+  --disable-largefile \
+  --without-zstd \
+  --with-system-zlib \
+  CC_FOR_BUILD=gcc \
+  AR_FOR_BUILD=ar \
+  CFLAGS_FOR_BUILD="-O2 -g" \
+  LDFLAGS_FOR_BUILD="" \
+  CC="$CC_WASM" \
+  AR="$AR" \
+  NM="$NM" \
+  RANLIB="$RANLIB" \
+  CFLAGS="$CFLAGS_WASM" \
+  LDFLAGS="$LDFLAGS_WASM"
+
+if [[ ! -f Makefile ]]; then
+  echo "[binutils] ERROR: configure failed to produce Makefile." >&2
+  exit 1
+fi
+
+# ----------------------------------------------------------------------
+# 5) Build ld and as
+# ----------------------------------------------------------------------
+echo "[binutils] building (make all-ld all-gas)…"
+make all-ld all-gas -j"$JOBS" V=1 MAKEINFO=true
+
+popd >/dev/null
+
+# ----------------------------------------------------------------------
+# 6) Post-process helper
+# ----------------------------------------------------------------------
+post_process_binary() {
+  local NAME="$1"
+  local SRC_BIN="$2"
+
+  if [[ ! -f "$SRC_BIN" ]]; then
+    echo "[binutils] ERROR: $NAME binary not produced at '$SRC_BIN'" >&2
+    return 1
+  fi
+
+  local WASM_FILE="$SCRIPT_DIR/${NAME}.wasm"
+  local OPT_WASM="$SCRIPT_DIR/${NAME}.opt.wasm"
+  cp "$SRC_BIN" "$WASM_FILE"
+  echo "[binutils] $NAME binary size: $(du -h "$WASM_FILE" | cut -f1)"
+
+  # --- wasm-opt ---
+  if [[ -x "$WASM_OPT" ]]; then
+    echo "[binutils] running wasm-opt on $NAME (epoch-injection + asyncify + O2)…"
+    "$WASM_OPT" --epoch-injection --asyncify \
+      --debuginfo -O2 \
+      "$WASM_FILE" -o "$OPT_WASM"
+  else
+    echo "[binutils] ERROR: wasm-opt not found at '$WASM_OPT'; exiting." >&2
+    exit 1
+  fi
+
+  if [[ ! -f "$OPT_WASM" ]]; then
+    echo "[binutils] ERROR: failed to generate '$OPT_WASM'; exiting." >&2
+    exit 1
+  fi
+
+  # --- lind-boot --precompile ---
+  if [[ ! -x "$LIND_BOOT" ]]; then
+    echo "[binutils] ERROR: lind-boot not found at '$LIND_BOOT'" >&2
+    exit 1
+  fi
+
+  echo "[binutils] generating cwasm for $NAME via lind-boot --precompile…"
+  "$LIND_BOOT" --precompile "$OPT_WASM"
+
+  local OPT_CWASM="$SCRIPT_DIR/${NAME}.opt.cwasm"
+  if [[ ! -f "$OPT_CWASM" ]]; then
+    echo "[binutils] ERROR: precompile produced no .cwasm for $NAME" >&2
+    exit 1
+  fi
+
+  cp "$OPT_CWASM" "$STAGE_DIR/$NAME"
+  echo "[binutils] $NAME staged as $STAGE_DIR/$NAME (precompiled)"
+}
+
+# ----------------------------------------------------------------------
+# 7) Stage ld and as
+# ----------------------------------------------------------------------
+LD_BIN="$BINUTILS_BUILD/ld/ld-new"
+AS_BIN="$BINUTILS_BUILD/gas/as-new"
+
+post_process_binary "ld" "$LD_BIN"
+post_process_binary "as" "$AS_BIN"
+
+popd >/dev/null 2>&1 || true
+
+echo
+echo "[binutils] build complete. Outputs under:"
+echo "  $STAGE_DIR"
+ls -lh "$STAGE_DIR" || true
diff --git a/gcc/clean.sh b/gcc/clean.sh
new file mode 100755
index 0000000000..b9ad097204
--- /dev/null
+++ b/gcc/clean.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+APPS_BUILD="$APPS_ROOT/build"
+
+rm -rf "$APPS_BUILD/gcc-build"
+rm -rf "$APPS_BUILD/gcc"
+rm -f "$SCRIPT_DIR/cc1.wasm" "$SCRIPT_DIR/cc1.opt.wasm" "$SCRIPT_DIR/cc1.opt.cwasm"
diff --git a/gcc/compile_gcc.sh b/gcc/compile_gcc.sh
new file mode 100755
index 0000000000..873e1739db
--- /dev/null
+++ b/gcc/compile_gcc.sh
@@ -0,0 +1,411 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+###############################################################################
+# GCC WASI build helper for lind-wasm-apps
+#
+# Cross-compiles GCC 15.2.0 (C language only) to wasm32-wasi so that cc1 can
+# run inside the Lind sandbox.  The resulting compiler targets x86_64-linux-gnu
+# (GCC has no wasm32 backend).
+#
+# High-level strategy:
+#   1. Download GCC prerequisites (GMP, MPFR, MPC) into the source tree
+#   2. Out-of-tree build (GCC requires this)
+#   3. Configure with --host=wasm32-unknown-wasi, --target=x86_64-linux-gnu
+#      Generator tools are built natively via CC_FOR_BUILD; cc1 is cross-
+#      compiled to wasm32 via CC/CXX.
+#   4. Build with 'make all-gcc' (compiler only, no target libraries)
+#   5. Stage cc1, post-process with wasm-opt + lind-boot
+#
+# Prerequisites:
+#   - Run 'make preflight' and ensure libc++ is in the merged sysroot
+#     (run 'make libcxx merge-sysroot' or let the Makefile handle it)
+#   - Native gcc/g++ must be on PATH (for CC_FOR_BUILD / CXX_FOR_BUILD)
+###############################################################################
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+GCC_SRC="$APPS_ROOT/gcc"
+
+APPS_BUILD="$APPS_ROOT/build"
+MERGED_SYSROOT="$APPS_BUILD/sysroot_merged"
+STAGE_DIR="$APPS_BUILD/gcc/usr/local/bin"
+TOOL_ENV="$APPS_BUILD/.toolchain.env"
+
+if [[ -z "${LIND_WASM_ROOT:-}" ]]; then
+  LIND_WASM_ROOT="$(cd "$APPS_ROOT/.." && pwd)"
+fi
+
+WASM_OPT="${WASM_OPT:-$LIND_WASM_ROOT/tools/binaryen/bin/wasm-opt}"
+LIND_BOOT="${LIND_BOOT:-$LIND_WASM_ROOT/build/lind-boot}"
+
+JOBS="${JOBS:-$(nproc 2>/dev/null || getconf _NPROCESSORS_ONLN || echo 4)}"
+
+# ----------------------------------------------------------------------
+# 1) Load toolchain from Makefile preflight
+# ----------------------------------------------------------------------
+if [[ -r "$TOOL_ENV" ]]; then
+  # shellcheck disable=SC1090
+  . "$TOOL_ENV"
+else
+  echo "[gcc] ERROR: missing toolchain env '$TOOL_ENV' (run 'make preflight' first)" >&2
+  exit 1
+fi
+
+: "${CLANG:?missing CLANG in $TOOL_ENV}"
+: "${AR:?missing AR in $TOOL_ENV}"
+: "${RANLIB:?missing RANLIB in $TOOL_ENV}"
+: "${NM:?missing NM in $TOOL_ENV}"
+
+LLVM_BIN_DIR="$(dirname "$CLANG")"
+CLANGXX="$LLVM_BIN_DIR/clang++"
+if [[ ! -x "$CLANGXX" ]]; then
+  echo "[gcc] WARN: clang++ not found; creating symlink to clang"
+  ln -sf "$CLANG" "$CLANGXX"
+fi
+
+# Sanity checks
+if [[ ! -d "$GCC_SRC" ]]; then
+  echo "[gcc] ERROR: GCC source dir not found at '$GCC_SRC'" >&2
+  exit 1
+fi
+if [[ ! -d "$MERGED_SYSROOT" ]]; then
+  echo "[gcc] ERROR: merged sysroot '$MERGED_SYSROOT' not found. Run 'make merge-sysroot' first." >&2
+  exit 1
+fi
+# libc++ must be in the sysroot for C++ compilation
+if [[ ! -f "$MERGED_SYSROOT/lib/wasm32-wasi/libc++.a" ]]; then
+  echo "[gcc] ERROR: libc++.a not found in merged sysroot. Run 'make libcxx merge-sysroot' first." >&2
+  exit 1
+fi
+# Need native gcc/g++ for building generator tools
+if ! command -v gcc &>/dev/null || ! command -v g++ &>/dev/null; then
+  echo "[gcc] ERROR: native gcc/g++ required for CC_FOR_BUILD but not found on PATH" >&2
+  exit 1
+fi
+
+mkdir -p "$STAGE_DIR"
+
+# ----------------------------------------------------------------------
+# 2) WASM toolchain flags
+# ----------------------------------------------------------------------
+LIBCXX_INCLUDE="$MERGED_SYSROOT/include/wasm32-wasi/c++/v1"
+
+# GCC's build system passes CFLAGS/CXXFLAGS to BOTH the cross-compiler (CC)
+# and the native build compiler (CC_FOR_BUILD).  ALL wasm-specific flags —
+# target, sysroot, include paths, -matomics, -mbulk-memory, libc++ — MUST
+# live in CC/CXX so that native g++ never sees them.
+CC_WASM="$CLANG --target=wasm32-unknown-wasi --sysroot=$MERGED_SYSROOT \
+  -pthread -matomics -mbulk-memory \
+  -I$MERGED_SYSROOT/include -I$MERGED_SYSROOT/include/wasm32-wasi"
+
+CXX_WASM="$CLANGXX --target=wasm32-unknown-wasi --sysroot=$MERGED_SYSROOT \
+  -pthread -matomics -mbulk-memory \
+  -stdlib=libc++ -isystem $LIBCXX_INCLUDE -fno-exceptions \
+  -I$MERGED_SYSROOT/include -I$MERGED_SYSROOT/include/wasm32-wasi"
+
+# CFLAGS/CXXFLAGS must contain ONLY portable flags that native g++ also
+# understands — no paths, no wasm flags.
+# Use -Os to minimize binary size — cc1 at -O2 is ~183MB which causes
+# wasm-opt --asyncify to OOM in Docker (no swap available).
+CFLAGS_WASM="-Os"
+CXXFLAGS_WASM="-Os"
+
+LDFLAGS_WASM="-Wl,--import-memory,--export-memory,--max-memory=67108864 \
+  -Wl,--export=__stack_pointer,--export=__stack_low,--export=__tls_base \
+  -L$MERGED_SYSROOT/lib/wasm32-wasi \
+  -L$MERGED_SYSROOT/usr/lib/wasm32-wasi \
+  -lc++ -lc++abi"
+
+echo "[gcc] using CLANG          = $CLANG"
+echo "[gcc] using CLANGXX        = $CLANGXX"
+echo "[gcc] using AR             = $AR"
+echo "[gcc] LIND_WASM_ROOT       = $LIND_WASM_ROOT"
+echo "[gcc] merged sysroot       = $MERGED_SYSROOT"
+echo "[gcc] libc++ headers       = $LIBCXX_INCLUDE"
+echo "[gcc] stage dir            = $STAGE_DIR"
+echo "[gcc] CC_WASM              = $CC_WASM"
+echo
+
+# ----------------------------------------------------------------------
+# 3) Download GCC prerequisites (GMP, MPFR, MPC) if not already present
+# ----------------------------------------------------------------------
+pushd "$GCC_SRC" >/dev/null
+
+if [[ ! -d gmp ]] || [[ ! -d mpfr ]] || [[ ! -d mpc ]]; then
+  echo "[gcc] downloading prerequisites (GMP, MPFR, MPC)…"
+  ./contrib/download_prerequisites --no-isl --no-verify
+fi
+
+# GMP/MPFR/MPC ship their own config.sub which is too old to know about
+# wasm32-wasi.  Overwrite with GCC's version which does.
+echo "[gcc] patching config.sub in prerequisites…"
+for dir in gmp mpfr mpc; do
+  if [[ -f "$dir/config.sub" ]]; then
+    cp -f config.sub "$dir/config.sub"
+    echo "[gcc]   updated $dir/config.sub"
+  fi
+  if [[ -f "$dir/configfsf.sub" ]]; then
+    cp -f config.sub "$dir/configfsf.sub"
+    echo "[gcc]   updated $dir/configfsf.sub"
+  fi
+done
+
+# Patch MPFR's configure to disable float128.
+# MPFR detects __float128 (clang accepts it), then adds -D_Float128=__float128
+# which conflicts with the WASI sysroot's "typedef __float128 _Float128;"
+# in bits/floatn.h.  MPFR's configure runs during 'make all-gcc', so we
+# patch the source-level configure script directly.
+MPFR_CONFIGURE="$GCC_SRC/mpfr/configure"
+if [[ -f "$MPFR_CONFIGURE" ]]; then
+  if ! grep -q 'PATCHED_FOR_WASI' "$MPFR_CONFIGURE"; then
+    echo "[gcc] [patch] disabling float128 in MPFR configure…"
+    # Insert enable_float128=no right after the shebang line
+    sed -i '1 a\enable_float128=no  # PATCHED_FOR_WASI' "$MPFR_CONFIGURE"
+    echo "[gcc] [patch] verify:"
+    head -3 "$MPFR_CONFIGURE"
+  else
+    echo "[gcc] MPFR configure already patched for WASI."
+  fi
+else
+  echo "[gcc] WARN: MPFR configure not found at $MPFR_CONFIGURE"
+fi
+
+# Also guard the sysroot's bits/floatn.h so the typedef doesn't conflict
+# when _Float128 is pre-defined as a macro (by MPFR or anything else).
+FLOATN_H="$MERGED_SYSROOT/include/wasm32-wasi/bits/floatn.h"
+if [[ -f "$FLOATN_H" ]] && ! grep -q 'PATCHED_FOR_WASI' "$FLOATN_H"; then
+  echo "[gcc] [patch] guarding _Float128 typedef in sysroot floatn.h…"
+  sed -i 's|^typedef __float128 _Float128;|/* PATCHED_FOR_WASI */\n#ifndef _Float128\ntypedef __float128 _Float128;\n#endif|' "$FLOATN_H"
+fi
+
+popd >/dev/null
+
+# ----------------------------------------------------------------------
+# 4) Out-of-tree build directory
+# ----------------------------------------------------------------------
+GCC_BUILD="$APPS_BUILD/gcc-build"
+mkdir -p "$GCC_BUILD"
+
+echo "[gcc] build dir = $GCC_BUILD"
+
+# ----------------------------------------------------------------------
+# 4b) Create config.site to override broken sub-configure detections
+# ----------------------------------------------------------------------
+# This lives here (not in a separate MPFR step) because GCC builds MPFR
+# in-tree as part of its own configure/make.  CONFIG_SITE is inherited by
+# all sub-configures, so setting it once in the top-level build directory
+# is the correct way to inject overrides into MPFR's autoconf.
+#
+# MPFR's configure detects __float128 support, then adds -D_Float128=__float128.
+# But the WASI sysroot already has "typedef __float128 _Float128;" in
+# bits/floatn.h, so the macro turns it into "typedef __float128 __float128;"
+# which is invalid.  Disable float128 in MPFR via configure cache.
+GCC_CONFIG_SITE="$GCC_BUILD/config.site"
+cat > "$GCC_CONFIG_SITE" << 'EOF'
+# Overrides for wasm32-wasi cross-compilation
+mpfr_cv_want_float128=no
+EOF
+export CONFIG_SITE="$GCC_CONFIG_SITE"
+echo "[gcc] created config.site: $GCC_CONFIG_SITE"
+
+# ----------------------------------------------------------------------
+# 5) Configure GCC
+# ----------------------------------------------------------------------
+BUILD_TRIPLET="$(gcc -dumpmachine 2>/dev/null || echo x86_64-linux-gnu)"
+
+echo "[gcc] configuring…"
+echo "[gcc]   --build=$BUILD_TRIPLET"
+echo "[gcc]   --host=wasm32-unknown-wasi"
+echo "[gcc]   --target=x86_64-linux-gnu"
+
+pushd "$GCC_BUILD" >/dev/null
+
+"$GCC_SRC/configure" \
+  --build="$BUILD_TRIPLET" \
+  --host=wasm32-unknown-wasi \
+  --target=x86_64-linux-gnu \
+  --disable-bootstrap \
+  --enable-languages=c \
+  --disable-shared \
+  --enable-static \
+  --disable-threads \
+  --disable-multilib \
+  --disable-plugin \
+  --disable-nls \
+  --disable-libgcc \
+  --disable-libssp \
+  --disable-libgomp \
+  --disable-libatomic \
+  --disable-libquadmath \
+  --disable-libvtv \
+  --disable-libitm \
+  --disable-libsanitizer \
+  --disable-libstdc++-v3 \
+  --disable-libffi \
+  --disable-decimal-float \
+  --disable-lto \
+  --disable-gcov \
+  --enable-checking=release \
+  --without-headers \
+  --without-isl \
+  --with-gnu-as \
+  --with-gnu-ld \
+  CC_FOR_BUILD=gcc \
+  CXX_FOR_BUILD=g++ \
+  AR_FOR_BUILD=ar \
+  CFLAGS_FOR_BUILD="-O2 -g" \
+  CXXFLAGS_FOR_BUILD="-O2 -g" \
+  LDFLAGS_FOR_BUILD="" \
+  CC="$CC_WASM" \
+  CXX="$CXX_WASM" \
+  AR="$AR" \
+  NM="$NM" \
+  RANLIB="$RANLIB" \
+  CFLAGS="$CFLAGS_WASM" \
+  CXXFLAGS="$CXXFLAGS_WASM" \
+  LDFLAGS="$LDFLAGS_WASM"
+
+if [[ ! -f Makefile ]]; then
+  echo "[gcc] ERROR: configure failed to produce Makefile." >&2
+  exit 1
+fi
+
+# ----------------------------------------------------------------------
+# 6) Build (compiler only — no target libraries)
+# ----------------------------------------------------------------------
+echo "[gcc] building (make all-gcc)…"
+make all-gcc -j"$JOBS" V=1
+
+popd >/dev/null
+
+# ----------------------------------------------------------------------
+# 7) Stage cc1 binary
+# ----------------------------------------------------------------------
+CC1_BIN="$GCC_BUILD/gcc/cc1"
+if [[ ! -f "$CC1_BIN" ]]; then
+  echo "[gcc] ERROR: cc1 binary not produced at '$CC1_BIN'" >&2
+  exit 1
+fi
+
+CC1_WASM="$SCRIPT_DIR/cc1.wasm"
+CC1_OPT_WASM="$SCRIPT_DIR/cc1.opt.wasm"
+cp "$CC1_BIN" "$CC1_WASM"
+
+echo "[gcc] cc1 binary size: $(du -h "$CC1_WASM" | cut -f1)"
+
+# ----------------------------------------------------------------------
+# 8) wasm-opt
+# ----------------------------------------------------------------------
+if [[ -x "$WASM_OPT" ]]; then
+  # Build an asyncify ignore list for functions that are too large to
+  # instrument.  Asyncify inflates auto-generated pattern matchers and
+  # template instantiations by 1000x+, causing cranelift's u32 DFG index
+  # to overflow during AOT precompilation.  These are all pure computation
+  # (no I/O or yield points) so skipping is safe.
+  #
+  # This is a permanent part of the build, not a temporary workaround —
+  # these auto-generated functions will always be too large for asyncify
+  # and will never contain yield points (they are pure tree/RTL rewrites).
+  #
+  #   gimple_simplify_*            — match.pd GIMPLE simplifiers
+  #   generic_simplify_*           — match.pd GENERIC simplifiers
+  #   gimple_bitwise_*, gimple_bit_*, gimple_power_* — match.pd exports
+  #   tree_power_*, tree_bitwise_* — match.pd GENERIC exports
+  #   types_match                  — match.pd helper
+  #   def_fn_type                  — builtin type init (runs once)
+  #   wi::*                        — wide-int template instantiations
+  #   fold_*                       — tree constant folding
+  #   recog*, extract_*            — insn-recog.c / insn-extract.c
+  #   output_NNN                   — insn-output.c emitters
+  #   gen_*                        — insn-emit.c generated code
+  #   simplify_*                   — RTL simplification
+  #   combine_*                    — instruction combiner
+  #   ix86_*, x86_*                — x86 backend (huge switch tables)
+  #   get_attr_*, internal_dfa*    — insn-attrtab.c scheduling tables
+  # Binaryen's asyncify-removelist supports * wildcards, so we use a
+  # small static pattern list instead of enumerating all 17K+ names.
+  ASYNCIFY_IGNORE="$SCRIPT_DIR/asyncify_ignore.txt"
+  cat > "$ASYNCIFY_IGNORE" << 'PATTERNS'
+gimple_simplify_*
+generic_simplify_*
+gimple_bitwise_*
+gimple_bit_*
+gimple_power_*
+gimple_maybe_*
+gimple_unsigned_integer_sat_*
+gimple_signed_integer_sat_*
+gimple_nop_convert*
+gimple_with_*
+tree_power_*
+tree_bitwise_*
+tree_bit_*
+tree_maybe_*
+tree_nop_convert*
+tree_with_*
+tree_unsigned_integer_sat_*
+tree_signed_integer_sat_*
+types_match
+def_fn_type
+wi::*
+fold_*
+recog*
+simplify_*
+combine_*
+ix86_*
+x86_*
+output_*
+gen_*
+extract_*
+get_attr_*
+internal_dfa*
+peephole2_*
+PATTERNS
+  IGNORE_COUNT=$(wc -l < "$ASYNCIFY_IGNORE")
+  echo "[gcc] asyncify removelist: $IGNORE_COUNT wildcard patterns"
+
+  # IMPORTANT: asyncify must run on cc1.wasm (which has the name section
+  # from wasm-ld) so that the removelist can match function names.
+  # Note: double @@ — first @ is pass-arg separator, second @ means
+  # "read from response file" (Binaryen convention).
+  echo "[gcc] running wasm-opt (epoch-injection + asyncify + strip + Os)…"
+  "$WASM_OPT" --epoch-injection --asyncify \
+    --pass-arg=asyncify-removelist@@"$ASYNCIFY_IGNORE" \
+    --strip-debug -Os \
+    "$CC1_WASM" -o "$CC1_OPT_WASM"
+else
+  echo "[gcc] ERROR: wasm-opt not found at '$WASM_OPT'; exiting." >&2
+  exit 1
+fi
+
+if [[ ! -f "$CC1_OPT_WASM" ]]; then
+  echo "[gcc] ERROR: Failed to generate '$CC1_OPT_WASM'; exiting." >&2
+  exit 1
+fi
+
+# ----------------------------------------------------------------------
+# 9) cwasm generation via lind-boot --precompile
+# ----------------------------------------------------------------------
+if [[ ! -x "$LIND_BOOT" ]]; then
+  echo "[gcc] ERROR: lind-boot not found at '$LIND_BOOT'"
+  exit 1
+fi
+
+echo "[gcc] generating cwasm via lind-boot --precompile…"
+"$LIND_BOOT" --precompile "$CC1_OPT_WASM"
+
+CC1_OPT_CWASM="$SCRIPT_DIR/cc1.opt.cwasm"
+if [[ ! -f "$CC1_OPT_CWASM" ]]; then
+  echo "[gcc] ERROR: precompile produced no .cwasm"
+  exit 1
+fi
+
+cp "$CC1_OPT_CWASM" "$STAGE_DIR/cc1"
+echo "[gcc] cc1 staged as $STAGE_DIR/cc1 (precompiled)"
+
+popd >/dev/null 2>&1 || true
+
+echo
+echo "[gcc] build complete. Outputs under:"
+echo "  $STAGE_DIR"
+ls -lh "$STAGE_DIR" || true
diff --git a/llvm-project/Toolchain-WASI.cmake.in b/llvm-project/Toolchain-WASI.cmake.in
new file mode 100644
index 0000000000..538efe9c87
--- /dev/null
+++ b/llvm-project/Toolchain-WASI.cmake.in
@@ -0,0 +1,25 @@
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR wasm32)
+
+set(CMAKE_C_COMPILER "@CLANG@")
+set(CMAKE_CXX_COMPILER "@CLANGXX@")
+set(CMAKE_AR "@AR@")
+set(CMAKE_NM "@NM@")
+set(CMAKE_RANLIB "@RANLIB@")
+set(CMAKE_SYSROOT "@BASE_SYSROOT@")
+
+set(CMAKE_C_COMPILER_TARGET wasm32-unknown-wasi)
+set(CMAKE_CXX_COMPILER_TARGET wasm32-unknown-wasi)
+
+set(CMAKE_C_FLAGS_INIT "-pthread -matomics -mbulk-memory -static -nostdlib -nodefaultlibs -fno-exceptions -fno-unwind-tables")
+set(CMAKE_CXX_FLAGS_INIT "-frtti -pthread -matomics -mbulk-memory -static -nostdlib -nodefaultlibs -fno-exceptions -stdlib=libc++ -fno-unwind-tables")
+set(CMAKE_EXE_LINKER_FLAGS_INIT "-static -nostdlib -nodefaultlibs")
+
+set(CMAKE_SKIP_RPATH ON)
+
+set(LLVM_HOST_TRIPLE "wasm32-wasip1")
+set(LLVM_DEFAULT_TARGET_TRIPLE "wasm32-wasip1")
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
diff --git a/llvm-project/clean.sh b/llvm-project/clean.sh
new file mode 100755
index 0000000000..5c53bce77c
--- /dev/null
+++ b/llvm-project/clean.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+APPS_BUILD="$APPS_ROOT/build"
+
+rm -rf "$APPS_BUILD/libcxx-build"
+rm -rf "$APPS_BUILD/libcxx-install"
diff --git a/llvm-project/compile_libcxx.sh b/llvm-project/compile_libcxx.sh
new file mode 100755
index 0000000000..46968352f4
--- /dev/null
+++ b/llvm-project/compile_libcxx.sh
@@ -0,0 +1,188 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+###############################################################################
+# libc++ / libc++abi WASI build helper for lind-wasm-apps
+#
+# Cross-compiles LLVM libc++ and libc++abi to wasm32-wasi using the toolchain
+# detected by the top-level Makefile preflight target.  Installs headers and
+# static libraries to the sysroot overlay so merge-sysroot can pick them up.
+#
+# Based on the approach in Lind-Project/lind-wasm PR #976.
+#
+# Prerequisites:
+#   - Run 'make preflight' first
+#   - cmake >= 3.20 must be on PATH
+###############################################################################
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+APPS_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+LLVM_SRC="$SCRIPT_DIR"
+
+APPS_BUILD="$APPS_ROOT/build"
+APPS_OVERLAY="$APPS_BUILD/sysroot_overlay"
+TOOL_ENV="$APPS_BUILD/.toolchain.env"
+
+if [[ -z "${LIND_WASM_ROOT:-}" ]]; then
+  LIND_WASM_ROOT="$(cd "$APPS_ROOT/.." && pwd)"
+fi
+
+BASE_SYSROOT="${BASE_SYSROOT:-$LIND_WASM_ROOT/src/glibc/sysroot}"
+
+JOBS="${JOBS:-$(nproc 2>/dev/null || getconf _NPROCESSORS_ONLN || echo 4)}"
+
+# ----------------------------------------------------------------------
+# 1) Load toolchain from Makefile preflight
+# ----------------------------------------------------------------------
+if [[ -r "$TOOL_ENV" ]]; then
+  # shellcheck disable=SC1090
+  . "$TOOL_ENV"
+else
+  echo "[libcxx] ERROR: missing toolchain env '$TOOL_ENV' (run 'make preflight' first)" >&2
+  exit 1
+fi
+
+: "${CLANG:?missing CLANG in $TOOL_ENV}"
+: "${AR:?missing AR in $TOOL_ENV}"
+: "${RANLIB:?missing RANLIB in $TOOL_ENV}"
+: "${NM:?missing NM in $TOOL_ENV}"
+
+LLVM_BIN_DIR="$(dirname "$CLANG")"
+# clang++ is typically a symlink next to clang
+CLANGXX="$LLVM_BIN_DIR/clang++"
+if [[ ! -x "$CLANGXX" ]]; then
+  echo "[libcxx] WARN: clang++ not found at '$CLANGXX'; creating symlink to clang"
+  ln -sf "$CLANG" "$CLANGXX"
+fi
+
+# Sanity checks
+if [[ ! -d "$LLVM_SRC/libcxx" ]]; then
+  echo "[libcxx] ERROR: libc++ source not found at '$LLVM_SRC/libcxx'" >&2
+  exit 1
+fi
+if [[ ! -d "$LLVM_SRC/libcxxabi" ]]; then
+  echo "[libcxx] ERROR: libc++abi source not found at '$LLVM_SRC/libcxxabi'" >&2
+  exit 1
+fi
+if [[ ! -r "$BASE_SYSROOT/include/wasm32-wasi/stdio.h" ]]; then
+  echo "[libcxx] ERROR: base sysroot headers missing at '$BASE_SYSROOT'" >&2
+  exit 1
+fi
+
+CMAKE="${CMAKE:-cmake}"
+if ! command -v "$CMAKE" &>/dev/null; then
+  echo "[libcxx] ERROR: cmake not found on PATH" >&2
+  exit 1
+fi
+
+BUILD_DIR="$APPS_BUILD/libcxx-build"
+INSTALL_DIR="$APPS_BUILD/libcxx-install"
+
+echo "[libcxx] using CLANG       = $CLANG"
+echo "[libcxx] using CLANGXX     = $CLANGXX"
+echo "[libcxx] using AR          = $AR"
+echo "[libcxx] using NM          = $NM"
+echo "[libcxx] LIND_WASM_ROOT    = $LIND_WASM_ROOT"
+echo "[libcxx] base sysroot      = $BASE_SYSROOT"
+echo "[libcxx] build dir         = $BUILD_DIR"
+echo "[libcxx] install dir       = $INSTALL_DIR"
+echo
+
+# ----------------------------------------------------------------------
+# 2) Patch libc++ time_utils.h (reinterpret_cast fix for WASI timespec)
+#    See: Lind-Project/lind-wasm PR #976
+# ----------------------------------------------------------------------
+TIME_UTILS="$LLVM_SRC/libcxx/src/filesystem/time_utils.h"
+if [[ -f "$TIME_UTILS" ]]; then
+  if grep -q 'reinterpret_cast<long\*>' "$TIME_UTILS"; then
+    echo "[libcxx] [patch] time_utils.h already patched; skipping."
+  else
+    python3 - <<'PY' "$TIME_UTILS"
+import pathlib, sys
+p = pathlib.Path(sys.argv[1])
+s = p.read_text(errors="ignore")
+
+old = "return set_times_checked(&dest.tv_sec, &dest.tv_nsec, tp);"
+new = "return set_times_checked(reinterpret_cast<long*>(&dest.tv_sec),\n                         reinterpret_cast<long*>(&dest.tv_nsec),\n                         tp);"
+
+if old in s:
+    p.write_text(s.replace(old, new))
+    print(f"[libcxx] [patch] added reinterpret_cast fix to {p}")
+else:
+    print(f"[libcxx] WARN: time_utils.h patch pattern not found in {p}", file=sys.stderr)
+PY
+  fi
+fi
+
+# ----------------------------------------------------------------------
+# 3) Generate CMake toolchain file for wasm32-wasi cross-compilation
+# ----------------------------------------------------------------------
+mkdir -p "$BUILD_DIR"
+
+TOOLCHAIN_FILE="$BUILD_DIR/Toolchain-WASI.cmake"
+sed -e "s|@CLANG@|$CLANG|g" \
+    -e "s|@CLANGXX@|$CLANGXX|g" \
+    -e "s|@AR@|$AR|g" \
+    -e "s|@NM@|$NM|g" \
+    -e "s|@RANLIB@|$RANLIB|g" \
+    -e "s|@BASE_SYSROOT@|$BASE_SYSROOT|g" \
+    "$SCRIPT_DIR/Toolchain-WASI.cmake.in" > "$TOOLCHAIN_FILE"
+
+echo "[libcxx] generated toolchain file: $TOOLCHAIN_FILE"
+
+# ----------------------------------------------------------------------
+# 4) Configure with CMake
+# ----------------------------------------------------------------------
+echo "[libcxx] configuring…"
+
+"$CMAKE" -B "$BUILD_DIR" -S "$LLVM_SRC/runtimes" \
+  -DCMAKE_TOOLCHAIN_FILE="$TOOLCHAIN_FILE" \
+  -DLLVM_PATH="$LLVM_SRC/llvm" \
+  -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" \
+  -DLIBCXX_ENABLE_SHARED=OFF \
+  -DLIBCXX_ENABLE_STATIC=ON \
+  -DLIBCXX_ENABLE_EXCEPTIONS=OFF \
+  -DLIBCXX_ENABLE_RTTI=ON \
+  -DLIBCXX_USE_COMPILER_RT=ON \
+  -DLIBCXX_ENABLE_UNWIND_TABLES=OFF \
+  -DLIBCXX_ENABLE_TIME_ZONE_DATABASE=OFF \
+  -DLIBCXX_HAS_MUSL_LIBC=OFF \
+  -DLIBCXXABI_ENABLE_SHARED=OFF \
+  -DLIBCXXABI_ENABLE_STATIC=ON \
+  -DLIBCXXABI_ENABLE_EXCEPTIONS=OFF \
+  -DLIBCXXABI_ENABLE_RTTI=ON \
+  -DLIBCXXABI_USE_LLVM_UNWINDER=OFF \
+  -DLIBCXXABI_ENABLE_STATIC_UNWINDER=OFF \
+  -DLIBCXXABI_ENABLE_UNWIND_TABLES=OFF \
+  -DLIBCXXABI_USE_COMPILER_RT=ON \
+  -DLIBCXXABI_LIBCXX_PATH="$LLVM_SRC/libcxx" \
+  -DCMAKE_BUILD_TYPE=Release \
+  -DCMAKE_INSTALL_PREFIX="$INSTALL_DIR" \
+  -DCMAKE_CXX_COMPILER_WORKS=1 \
+  -DCMAKE_C_COMPILER_WORKS=1
+
+# ----------------------------------------------------------------------
+# 5) Build and install
+# ----------------------------------------------------------------------
+echo "[libcxx] building…"
+"$CMAKE" --build "$BUILD_DIR" --target install -j"$JOBS"
+
+# ----------------------------------------------------------------------
+# 6) Copy headers and libs to sysroot overlay
+# ----------------------------------------------------------------------
+echo "[libcxx] installing to sysroot overlay…"
+
+# Headers: overlay/usr/include/c++/v1/ (merge step puts them at include/wasm32-wasi/c++/v1/)
+mkdir -p "$APPS_OVERLAY/usr/include/c++"
+cp -r "$INSTALL_DIR/include/c++/"* "$APPS_OVERLAY/usr/include/c++/"
+
+# Static libraries
+mkdir -p "$APPS_OVERLAY/usr/lib/wasm32-wasi"
+cp "$INSTALL_DIR/lib/libc++.a"    "$APPS_OVERLAY/usr/lib/wasm32-wasi/"
+cp "$INSTALL_DIR/lib/libc++abi.a" "$APPS_OVERLAY/usr/lib/wasm32-wasi/"
+
+echo
+echo "[libcxx] build complete. Outputs:"
+echo "  headers: $APPS_OVERLAY/usr/include/c++/"
+echo "  libs:    $APPS_OVERLAY/usr/lib/wasm32-wasi/"
+ls -lh "$APPS_OVERLAY/usr/lib/wasm32-wasi/libc++"* || true