--- lib/libxview/base/xv_debug.h.orig	1993-06-29 07:14:44.000000000 +0200
+++ lib/libxview/base/xv_debug.h	2003-12-30 02:51:57.000000000 +0100
@@ -9,12 +9,17 @@
 #ifndef _xv_debug_h_already_included
 #define _xv_debug_h_already_included
 
+#ifdef NULL
+#undef NULL
+#endif
 #ifndef FILE
 #ifndef SVR4
-#undef NULL
-#endif SVR4
+#endif /* SVR4 */
 #include <stdio.h>
-#endif FILE
+#ifndef NULL
+#define NULL 0
+#endif
+#endif /* FILE */
 #include <xview/pkg.h>		/* needed to get definition of Xv_private */
   /* 
    * Not strictly necessary to include <stdio.h> here, but eliminates
@@ -88,7 +93,7 @@ typedef enum {
  * xv_got_debugger to TRUE from the debugger.
  */
 
-#else _XV_DEBUG
+#else /* _XV_DEBUG */
 
 #define DEBUG_ONLY(x)
 #define AN_ERROR(expr, flag)	(expr)
@@ -97,6 +102,6 @@ typedef enum {
 #define FATAL_ERROR(exit_code)	if (xv_abort_fatal_error) abort() \
 				else exit(exit_code)
 
-#endif _XV_DEBUG
+#endif /* _XV_DEBUG */
 
-#endif _xv_debug_h_already_included
+#endif /* _xv_debug_h_already_included */
