#ifndef POSIXSOURCE_H
#define POSIXSOURCE_H
+#include <ghcplatform.h>
+
+#if defined(freebsd_HOST_OS)
+#define _POSIX_C_SOURCE 200112L
+#define _XOPEN_SOURCE 600
+#else
#define _POSIX_SOURCE 1
#define _POSIX_C_SOURCE 199506L
-#define _ISOC9X_SOURCE
+#define _XOPEN_SOURCE 500
+// FreeBSD takes a different approach to _ISOC99_SOURCE: on FreeBSD it
+// means "I want *just* C99 things", whereas on GNU libc and Solaris
+// it means "I also want C99 things".
+//
+// On both GNU libc and FreeBSD, _ISOC99_SOURCE is implied by
+// _XOPEN_SOURCE==600, but on Solaris it is an error to omit it.
+#define _ISOC99_SOURCE
+#endif
-/* Let's be ISO C9X too... */
+#if defined(darwin_HOST_OS)
+/* If we don't define this the including sysctl breaks with things like
+ /usr/include/bsm/audit.h:224:0:
+ error: syntax error before 'u_char'
+*/
+#define _DARWIN_C_SOURCE 1
+#endif
#endif /* POSIXSOURCE_H */