diff -Naur libxslt-1.0.30/libxslt/variables.c libxslt-1.0.30-warnings/libxslt/variables.c
--- libxslt-1.0.30/libxslt/variables.c	2003-04-30 14:57:35.000000000 -0500
+++ libxslt-1.0.30-warnings/libxslt/variables.c	2003-05-19 20:38:48.000000000 -0500
@@ -852,6 +852,7 @@
     xmlNsPtr *oldNamespaces;
     xsltStackElemPtr elem;
     int res;
+    void *res_ptr;
 
     if (ctxt == NULL)
 	return(-1);
@@ -901,8 +902,8 @@
     if (ncname == NULL)
 	return (-1);
 
-    res = xmlHashLookup2(ctxt->globalVars, ncname, href);
-    if (res != 0) {
+    res_ptr = xmlHashLookup2(ctxt->globalVars, ncname, href);
+    if (res_ptr != NULL) {
 	xsltTransformError(ctxt, style, NULL,
 	    "Global parameter %s already defined\n", ncname);
     }
