[libc-commits] [libc] [libc][math][c23] Add acospif16() function (PR #134664)

[via libc-commits]

amemov wrote:

@Intue - I think this time I did not miss anything - triple checked the files I committed and everything seems to be in order. It says for some reason that acospi is undeclared in MPFR - I guess it is what @overmighty in the previous PR I created?
```
FAILED: projects/libc/utils/MPFRWrapper/CMakeFiles/libcMPCommon.dir/MPCommon.cpp.o 

/var/lib/buildkite-agent/builds/linux-56-59b8f5d88-clshd-1/llvm-project/github-pull-requests/libc/utils/MPFRWrapper/MPCommon.cpp:69:3:  error:  use of undeclared identifier 'mpfr_acospi' 
```

https://github.com/llvm/llvm-project/pull/134664