On SUNOS4, include "md/sunos4.h" to get the macro definition of strerror.

(contributed by Brian Ostrom <briano@netscape.com>)

nsprpub/pr/src/misc/prerrortable.c

@@ -34,6 +34,9 @@ provided "as is" without express or implied warranty.
 */
 
 #include <string.h>
+#ifdef SUNOS4
+#include "md/sunos4.h"  /* for strerror */
+#endif
 #include <assert.h>
 #include <errno.h>
 #include "prmem.h"