[libc] Fix accidental inclusion of system libc headers.
Summary:
I found that because `--system-headers` flag was not included when running clang-tidy, errors produced from compiler provided headers were being suppressed. After passing this flag I realized that by including headers like stdint.h we were indirectly including headers from the system libc. To prevent this we pass `-ffreestanding`.
We don't want to pass `--system-headers` for all checks just the `llvmlibc-restrict-system-libc-headers` therefore we do a separate invocation of clang-tidy for this check.
Reviewers: abrachet, sivachandra
Reviewed By: sivachandra
Subscribers: mgorny, aheejin, tschuett, ecnelises, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D80178
GitOrigin-RevId: b2a485e37edf6415701c472d93afa7fa26dbcccb
2 files changed
