Merge #17919: depends: Allow building with system clang

de4fedb6c3a45e6a23f1bccd28045d76b5830afc depends: Add documentation for FORCE_USE_SYSTEM_CLANG make flag (Carl Dong)
fe98999dcf87ac056d0a2c9231fb3160abdf3417 depends: Reformat make options as definition list (Carl Dong)
60c55b1b9bab8c1e143e2f4c26d729bfa0bbcf09 depends: Add justifications for macOS clang flags (Carl Dong)
6b8e497eeaf38f272715c490f317fdc98a2174be depends: specify libc++ header location for darwin (Cory Fields)
156b604203ef17b2b77ee9dacf15e375c809242a depends: force a new host id string if FORCE_USE_SYSTEM_CLANG is in use (Cory Fields)
c9c572a367f08095a3e2c7c0723da9f6778b9378 depends: Allow building with system clang (Carl Dong)
e6e5c8d6caccb4648fc580e5a01448857c2fdf18 depends: Decouple toolchain + binutils (Carl Dong)

Pull request description:

  This replaces: #17099

  -----

  This patchset allows us to force depends to use system clang.

  Previously, #17099 removes our dependency on a specific clang we download from llvm.org, but theuni pointed out that since OSX builds are only ever built with a version of clang that is chosen and "blessed" by Apple, it is more likely that the user will encounter problems if they use their system clang. This patchset forces the user to set `FORCE_USE_SYSTEM_CLANG=1` in order to use their system clang (when they know what they're doing)

ACKs for top commit:
  theuni:
    ACK de4fedb6c3a45e6a23f1bccd28045d76b5830afc.

Tree-SHA512: 8774121e035f90c27030bcce06e1b79f7729b5e17802c718e49652ab06e19780632db974df47423c1d1b04f1ab1b7a763554fb922fec05d1cd6445b26578be1d

0 files changed, 0 insertions, 0 deletions