port patch from Marcus Meissner to add gcc checking for printf like

* include/libxml/parser.h include/libxml/xmlwriter.h
  include/libxml/relaxng.h include/libxml/xmlversion.h.in
  include/libxml/xmlwin32version.h.in include/libxml/valid.h
  include/libxml/xmlschemas.h include/libxml/xmlerror.h:
  port patch from Marcus Meissner to add gcc checking for
  printf like functions parameters, should fix #65068
* doc/apibuild.py doc/*: modified the script accordingly
  and regenerated
* xpath.c xmlmemory.c threads.c: fix a few warnings
Daniel

svn path=/trunk/; revision=3813
diff --git a/threads.c b/threads.c
index ef87763..2223e8a 100644
--- a/threads.c
+++ b/threads.c
@@ -919,7 +919,7 @@
     }
     DeleteCriticalSection(&cleanup_helpers_cs);
 #elif defined HAVE_PTHREAD_H
-    if ((pthread_key_delete != NULL) && (globalkey != NULL))
+    if ((libxml_is_threaded)  && (pthread_key_delete != NULL))
         pthread_key_delete(globalkey);
 #endif
 }