somewhat protect Mac OS X users from using Mac OS 9 config file

lib/config-mac.h

+#ifndef __LIB_CONFIG_MAC_H
+#define __LIB_CONFIG_MAC_H
+
+/* ================================================================ */
+/*    lib/config-mac.h - Hand crafted config file for Mac OS 9      */
+/* ================================================================ */
+/*   On Mac OS X you must run configure to generate config.h file   */
+/* ================================================================ */
+
 #define OS "mac"
 
 #define HAVE_NETINET_IN_H       1
@@ -83,3 +92,5 @@
 
 #define HAVE_EXTRA_STRICMP_H 1
 #define HAVE_EXTRA_STRDUP_H  1
+
+#endif /* __LIB_CONFIG_MAC_H */

lib/setup.h

@@ -48,8 +48,8 @@
 #endif
 #endif
 
-#ifdef macintosh
-#include "config-mac.h"
+#if defined(macintosh) && defined(__MRC__)
+#  include "config-mac.h"
 #endif
 
 #ifdef __AMIGA__

src/config-mac.h

+#ifndef __SRC_CONFIG_MAC_H
+#define __SRC_CONFIG_MAC_H
+
+/* ================================================================ */
+/*    src/config-mac.h - Hand crafted config file for Mac OS 9      */
+/* ================================================================ */
+/*   On Mac OS X you must run configure to generate config.h file   */
+/* ================================================================ */
+
 /* Define to 1 if you want the built-in manual */
 #define USE_MANUAL 1
 
@@ -19,3 +28,5 @@
 
 /* we provide our own strdup prototype */
 char *strdup(char *s1);
+
+#endif /* __SRC_CONFIG_MAC_H */

src/setup.h

@@ -46,8 +46,8 @@
 #include "config-win32.h"
 #endif
 
-#ifdef macintosh
-#include "config-mac.h"
+#if defined(macintosh) && defined(__MRC__)
+#  include "config-mac.h"
 #endif
 
 #ifdef __riscos__