Adds build scripts and Makefile integration for cross-compiling a complete C compilation toolchain to run inside the Lind sandbox: GCC 15.2.0 (cc1), GNU Binutils 2.46.0 (ld, as), and LLVM libc++/libc++abi. Together these provide the full preprocess → compile → assemble → link pipeline targeting x86_64-linux-gnu from within WASI.

libc++ (llvm-project/compile_libcxx.sh)

• Cross-compiles LLVM libc++ and libc++abi to wasm32-wasi using CMake
• Based on the approach from Libcpp compilation integration lind-wasm#976 by @123R3N321
• Installs headers and static libraries (libc++.a, libc++abi.a) to the sysroot overlay
• Required by GCC's C++ source code (GCC is written in C++)
• Makefile: make libcxx, merged via merge-libcxx stamp into the sysroot

GCC (gcc/compile_gcc.sh)

• Cross-compiles GCC 15.2.0 (C language only) with --host=wasm32-unknown-wasi --target=x86_64-linux-gnu
• Builds GMP, MPFR, MPC prerequisites in-tree; patches config.sub and MPFR float128 detection for WASI compatibility
• Uses -Os to minimize binary size; requires libc++ in the merged sysroot for GCC's C++ source
• Asyncify removelist with wildcard patterns to prevent Cranelift AOT precompilation failures caused by auto-generated match.pd pattern matchers, x86 backend switch tables, and wide-int template instantiations inflating 1000x+ under asyncify instrumentation
• Falls back to staging the .wasm for JIT compilation if AOT precompile still fails

Binutils (binutils/compile_binutils.sh)

• Cross-compiles GNU Binutils 2.46.0 with the same host/target triplets as GCC
• Builds only ld and as (make all-ld all-gas), skipping gold, gdb, gprofng, sim
• Pure C — no libc++ dependency; depends on zlib in the merged sysroot (for BFD compressed section support)
• Shared post_process_binary helper handles wasm-opt + lind-boot for both binaries

Makefile

• make libcxx — builds libc++/libc++abi, merged into sysroot via merge-libcxx stamp
• make gcc — depends on merge-libcxx
• make binutils — depends on merge-zlib
• make install-gcc / make install-binutils — stage into $LINDFS_ROOT
• Added to make install aggregate and make clean

Key technical details

• Asyncify removelist uses Binaryen's @@ response file syntax with * wildcard glob matching (--pass-arg=asyncify-removelist@@file.txt)
• --strip-debug must run AFTER asyncify (not before) so the wasm name section is available for removelist matching
• Generator tools (genrecog, gengtype, etc.) are built natively via CC_FOR_BUILD=gcc