Fixed Mac OS crash when using Fl_Native_File_Chooser with filter that does not end with \n.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@9029 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

src/Fl_Native_File_Chooser_MAC.mm

@@ -399,7 +399,7 @@ static char *prepareMacFilter(int count, const char *filter, char **patterns) {
     }
     rank++;
     *(q++) = '\n'; 
-    if (*p) p = r + 1;
+    if (*r) p = r + 1; else p = r;
   } while(*p);
   *q = 0;
   return t;