This function is missing on many non-glibc platforms:
MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11,
IRIX 6.5, OSF/1 5.1, Solaris 11 2011-11, Cygwin 1.7.1, mingw, MSVC 9, Interix 3.5, BeOS.
+But the replacement function is not atomic in multi-threaded programs.
@end itemize
Portability problems not fixed by Gnulib: