[libcxx-commits] [libcxx] [libcxx] Fix build for glibc < 2.27 (PR #121893)

[Louis Dionne via libcxx-commits]

================
@@ -39,8 +39,8 @@
 #include <fcntl.h> /* values for fchmodat */
 #include <time.h>
 
-// since Linux 4.5 and FreeBSD 13, but the Linux libc wrapper is only provided by glibc and musl
-#if (defined(__linux__) && (defined(__GLIBC__) || _LIBCPP_HAS_MUSL_LIBC)) || defined(__FreeBSD__)
+// since Linux 4.5 and FreeBSD 13, but the Linux libc wrapper is only provided by glibc >= 2.27 and musl
+#if (defined(__linux__) && (_LIBCPP_GLIBC_PREREQ(2, 27) || _LIBCPP_HAS_MUSL_LIBC)) || defined(__FreeBSD__)
----------------
ldionne wrote:

```suggestion
#if (defined(__linux__) && ((defined(_LIBCPP_GLIBC_PREREQ) && _LIBCPP_GLIBC_PREREQ(2, 27)) || _LIBCPP_HAS_MUSL_LIBC)) || defined(__FreeBSD__)
```

https://github.com/llvm/llvm-project/pull/121893