Extend php_namewarn_rename to act as a regression test for the warning about built-in function names used in %extend

Examples/test-suite/php_namewarn_rename.i

@@ -7,6 +7,11 @@
 %warnfilter(SWIGWARN_PARSE_KEYWORD) Hello::empty();
 #endif
 
+%ignore prev::operator++;
+%extend prev {
+  void next() { ++(*self); }
+}
+
 %inline %{
 
   int Exception() { return 13; }
@@ -26,4 +31,9 @@
     void empty() {}
   };
 
+  struct prev {
+    prev & operator++() { }
+    prev operator++(int) { }
+  };
+
 %}