a lot of small cleanups based on Linus' sparse check output. Daniel

* HTMLparser.c SAX2.c encoding.c globals.c parser.c relaxng.c
  runsuite.c runtest.c schematron.c testHTML.c testReader.c
  testRegexp.c testSAX.c testThreads.c valid.c xinclude.c xmlIO.c
  xmllint.c xmlmodule.c xmlschemas.c xpath.c xpointer.c: a lot of
  small cleanups based on Linus' sparse check output.
Daniel
diff --git a/xmlIO.c b/xmlIO.c
index a000e8c..0902a2f 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -1206,7 +1206,7 @@
     }
 
     /*  Set the header data.  The CRC will be needed for the trailer  */
-    buff->crc = crc32( 0L, Z_NULL, 0 );
+    buff->crc = crc32( 0L, NULL, 0 );
     hdr_lgth = snprintf( (char *)buff->zbuff, buff->size,
 			"%c%c%c%c%c%c%c%c%c%c",
 			GZ_MAGIC1, GZ_MAGIC2, Z_DEFLATED,