For the benefit of SunOS 4.1.4, define MS_SYNC as 0 when it's

undefined.  ccording to MvL, this is safe: the MS_SYNC flag means that
msync() returns when all I/O operations are scheduled; without it, it
waits until they are complete, which is acceptable behavior.

Modules/mmapmodule.c

@@ -32,8 +32,14 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
+
+#ifndef MS_SYNC
+/* This is missing e.g. on SunOS 4.1.4 */
+#define MS_SYNC 0
 #endif
 
+#endif /* UNIX */
+
 #include <string.h>
 #include <sys/types.h>