- multithread-safe on glibc systems, but is not required to be multithread-
- safe by POSIX. sprintf(), however, is multithread-safe. localeconv()
- is rarely multithread-safe. */
-# if HAVE_NL_LANGINFO && __GLIBC__
+ multithread-safe on glibc systems and MacOS X systems, but is not required
+ to be multithread-safe by POSIX. sprintf(), however, is multithread-safe.
+ localeconv() is rarely multithread-safe. */
+# if HAVE_NL_LANGINFO && (__GLIBC__ || (defined __APPLE__ && defined __MACH__))