Fix Bazel build by skipping C++ library linking

Set SPIRV_TOOLS_FFI_SKIP_CPP_LINK=1 in the Bazel build script so that
build.rs doesn't try to link SPIRV-Tools C++ libraries during cargo
build. Bazel handles the final linking separately.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: LegNeato

rust/scripts/build_rust_ffi.py

@@ -51,6 +51,8 @@ def main() -> int:
 
     env = os.environ.copy()
     env["CARGO_TARGET_DIR"] = str(target_dir)
+    # Skip linking C++ SPIRV-Tools libraries - Bazel will link them at final link time
+    env["SPIRV_TOOLS_FFI_SKIP_CPP_LINK"] = "1"
 
     package = args.package
     command = [