removed the last occurences of strdup usage in the code Daniel

* globals.c xmlIO.c xmlcatalog.c: removed the last occurences
  of strdup usage in the code
Daniel
diff --git a/globals.c b/globals.c
index a66f0e8..d3e3feb 100644
--- a/globals.c
+++ b/globals.c
@@ -287,7 +287,7 @@
     gs->xmlFree = (xmlFreeFunc) free;
     gs->xmlMalloc = (xmlMallocFunc) malloc;
     gs->xmlRealloc = (xmlReallocFunc) realloc;
-    gs->xmlMemStrdup = (xmlStrdupFunc) strdup;
+    gs->xmlMemStrdup = (xmlStrdupFunc) xmlStrdup;
 #endif
     gs->xmlGenericErrorContext = NULL;
     gs->xmlGetWarningsDefaultValue = 1;