repositioned #include for libxml.h to avoid compilation error on some

* testAutomata.c, testRegexp.c, testThreads.c, testThreadsWin32.c,
  xmlwriter.c: repositioned #include for libxml.h to avoid
  compilation error on some architectures (bug #398277)

svn path=/trunk/; revision=3578
diff --git a/xmlwriter.c b/xmlwriter.c
index 74838e6..2e67a4f 100644
--- a/xmlwriter.c
+++ b/xmlwriter.c
@@ -9,9 +9,9 @@
  */
 
 #define IN_LIBXML
+#include "libxml.h"
 #include <string.h>
 
-#include "libxml.h"
 #include <libxml/xmlmemory.h>
 #include <libxml/parser.h>
 #include <libxml/uri.h>