apply a couple of fixes based on a Coverity report forwarded by Derrick

* catalog.c: apply a couple of fixes based on a Coverity report
  forwarded by Derrick Price.
* VxWorks/README VxWorks/Makefile VxWorks/build.sh: instructions
  Makefile, and shell script to build on VxWorks 6.4+ provided by
  Jim Wert.
Daniel

svn path=/trunk/; revision=3747
diff --git a/catalog.c b/catalog.c
index ee3f8f2..af84b7c 100644
--- a/catalog.c
+++ b/catalog.c
@@ -2616,6 +2616,8 @@
 	return(ret);
     if (sysID != NULL)
 	ret = xmlCatalogGetSGMLSystem(catal->sgml, sysID);
+    if (ret != NULL)
+	return(ret);
     return(NULL);
 }
 
@@ -2912,7 +2914,7 @@
 
 	sgml = xmlCatalogSGMLResolve(catal, NULL, URI);
 	if (sgml != NULL)
-            sgml = xmlStrdup(sgml);
+            ret = xmlStrdup(sgml);
     }
     return(ret);
 }