Rewrite for MacOS-X compatibility fixes and enhancements plus some bugfixes.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@26181 72102866-910b-0410-8b05-ffd578937521

Source/NSNull.m

@@ -26,6 +26,7 @@
    */
 
 #include "Foundation/NSNull.h"
+#include "Foundation/NSString.h"
 
 /**
  * An object to use as a placeholder - in collections for instance.
@@ -81,6 +82,11 @@ static NSNull	*null = 0;
   GSNOSUPERDEALLOC;
 }
 
+- (NSString*) description
+{
+  return @"<null>";
+}
+
 - (void) encodeWithCoder: (NSCoder*)aCoder
 {
 }