Move xml2's PG_MODULE_MAGIC block to the right source file, per Michael Fuhr.

contrib/xml2/xpath.c

@@ -16,6 +16,9 @@
 #include <libxml/xmlerror.h>
 #include <libxml/parserInternals.h>
 
+
+PG_MODULE_MAGIC;
+
 /* declarations */
 
 static void *pgxml_palloc(size_t size);

contrib/xml2/xslt_proc.c

@@ -21,8 +21,6 @@
 #include <libxslt/xsltutils.h>
 
 
-PG_MODULE_MAGIC;
-
 /* declarations to come from xpath.c */
 
 extern void elog_error(int level, char *explain, int force);