diff -ru langtag.orig/extensions/lt-ext-ldml-u.c langtag/extensions/lt-ext-ldml-u.c
--- UnpackedTarball/langtag.orig/extensions/lt-ext-ldml-u.c	2013-04-22 10:06:56.000000000 +0200
+++ UnpackedTarball/langtag/extensions/lt-ext-ldml-u.c	2013-04-30 12:56:19.557490167 +0200
@@ -137,7 +137,11 @@
 							if (!strchr(hexdigit, subtag[j]))
 								goto bail2;
 						}
+#ifdef _WIN32
+						x = _strtoui64(subtag, &p, 16);
+#else
 						x = strtoull(subtag, &p, 16);
+#endif
 						if (p && p[0] == 0 && x <= 0x10ffff) {
 							retval = TRUE;
 							xmlFree(name);