## Why
Native voice builds ignore ambient compiler flags, but need a way to accept declared compiler, linker, and archive-tool inputs.
## What changed
- Add repeated `--c-flag`, `--cxx-flag`, and `--link-flag` options plus optional `--ar` and `--ranlib` paths for Unix builds. Record flags and pass them through CMake, Meson, and libffi, including Objective-C flags on macOS.
- Preserve literal libffi compiler arguments with response files. Reject flags containing whitespace, libffi paths requiring shell quoting, and Unix toolchain overrides on Windows.
- Add a pinned Bazel `pkg-config` tool built with LLVM archive tools and native macOS configure checks. Register the pinned Make toolchain and patch its bootstrap to pass preprocessor flags and enable cross-compilation configuration.
## Testing
Extend native-build tests to verify compiler and linker flags, explicit archive tools, Meson and Objective-C inputs, literal definitions through shell and recursive Make expansion, and rejection of unsupported overrides.
GitOrigin-RevId: e5ea541ec76abfa170f6b0411b0f14cd698c07e7
