Make non-ASCII strings in ui files work

Our extractor tool was not calling setlocale(), thus it only
produced output in the C locale, ie ASCII. Oops.

util/extract-strings.c

@@ -15,6 +15,7 @@
  * License along with this library. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <locale.h>
 #include <glib.h>
 
 typedef struct {
@@ -143,6 +144,8 @@ main (int argc, char *argv[])
   GMarkupParseContext *context;
   ParserData data;
 
+  setlocale (LC_ALL, "");
+
   if (argc < 2)
     {
       g_printerr ("Expect a filename\n");