Address comments

Author: jhuber6

libcxx/include/__configuration/platform.h

@@ -30,16 +30,17 @@
 // ... add new file formats here ...
 #endif
 
-// Need to detect which libc we're using if we're on Linux.
-#if defined(__linux__)
+// To detect which libc we're using
+#if __has_include(<features.h>)
 #  include <features.h>
+#endif
+
+#if defined(__linux__)
 #  if defined(__GLIBC_PREREQ)
 #    define _LIBCPP_GLIBC_PREREQ(a, b) __GLIBC_PREREQ(a, b)
 #  else
 #    define _LIBCPP_GLIBC_PREREQ(a, b) 0
 #  endif // defined(__GLIBC_PREREQ)
-#elif defined(__AMDGPU__) || defined(__NVPTX__)
-#  include <features.h>
 #endif
 
 #ifndef __BYTE_ORDER__