Revert "[libc++abi] Stop copying headers to the build directory"#115232

arichardson merged 1 commit intomainllvm/llvm-project:mainfrom

revert-115086-users/arichardson/spr/libcabi-stop-copying-headers-to-the-build-directoryllvm/llvm-project:revert-115086-users/arichardson/spr/libcabi-stop-copying-headers-to-the-build-directoryCopy head branch name to clipboard