llvm-project

b586da6c - [libc][bazel] Allow building with -DLIBC_FULL_BUILD (#218992)

[libc][bazel] Allow building with -DLIBC_FULL_BUILD (#218992) This PR defines a flag `--@llvm-project//libc:build_mode` that configures LLVM-libc to build with full-build flags. This is only compatible with clang at the moment, since it relies on the `-nostdlibinc` flag. This PR contains the logic for LLVM-libc full build in Bazel. A largely AI generated follow-on PR has `libc/BUILD.bazel` changes for building libc targets in full-build mode: https://github.com/llvm/llvm-project/pull/218993.