[libcxx-commits] [libcxx] [libcxx] Do not redeclare `lgamma_r` when targeting the LLVM C library (PR #102036)

[Louis Dionne via libcxx-commits]

================
@@ -38,7 +38,9 @@
 #  else
 #    define _LIBCPP_GLIBC_PREREQ(a, b) 0
 #  endif // defined(__GLIBC_PREREQ)
-#endif   // defined(__linux__)
+#elif defined(__AMDGPU__) || defined(__NVPTX__)
----------------
ldionne wrote:

This makes me wonder if we should instead do this:

```
// <features.h> defines macros that allows detecting the libc we're using
#if __has_include(<features.h>)
#  include <features.h>
#endif
#if defined(__GLIBC_PREREQ)
  // etc...
#endif
```

Can you try that out and see if that breaks anything in the CI?

https://github.com/llvm/llvm-project/pull/102036