patch to let glib access timezone info on OS X

glib-gtimezone.diff

diff --git a/glib/gtimezone.c b/glib/gtimezone.c
index 8195106..08125ff 100644
--- a/glib/gtimezone.c
+++ b/glib/gtimezone.c
@@ -168,8 +168,12 @@ again:
           G_UNLOCK(time_zones);
         }
 
-      if (tz->zoneinfo)
+      if (tz->zoneinfo) {
+        if (tz->header && tz->header->tzh_version != '2')
+          g_free (tz->trans);
+
         g_bytes_unref (tz->zoneinfo);
+      }
 
       g_free (tz->name);
 
@@ -408,13 +412,13 @@ g_time_zone_new (const gchar *identifier)
           gsize size;
           const struct tzhead *header = g_bytes_get_data (tz->zoneinfo, &size);
 
-          /* we only bother to support version 2 */
-          if (size < sizeof (struct tzhead) || memcmp (header, "TZif2", 5))
+          /* check that it is a TZif file */
+          if (size < sizeof (struct tzhead) || memcmp (header, "TZif", 4))
             {
               g_bytes_unref (tz->zoneinfo);
               tz->zoneinfo = NULL;
             }
-          else
+          else if (header->tzh_version == '2')	/* version 2 */
             {
               gint typecnt;
 
@@ -435,6 +439,28 @@ g_time_zone_new (const gchar *identifier)
               tz->infos   = (gconstpointer) (tz->indices + tz->timecnt);
               tz->abbrs   = (gconstpointer) (tz->infos + typecnt);
             }
+          else	/* assume version 1 */
+            {
+              gint typecnt, i;
+
+              /* use first header */
+              tz->header = header;
+              typecnt     = guint32_from_be (tz->header->tzh_typecnt);
+              tz->timecnt = guint32_from_be (tz->header->tzh_timecnt);
+
+              /* in version 1, transition times are 4 bytes long, so we need to convert them */
+              const gint32_be *trans32 = (gconstpointer) (tz->header + 1);
+              gint64_be *trans64 = g_malloc (sizeof (*tz->trans) * tz->timecnt);
+              for (i = 0; i < tz->timecnt; i++) {
+                gint64 tmp = GINT64_TO_BE (gint32_from_be (trans32[i]));
+                memcpy (&trans64[i], &tmp, sizeof tmp);
+              }
+              tz->trans	  = trans64;
+
+              tz->indices = (gconstpointer) (trans32 + tz->timecnt);
+              tz->infos   = (gconstpointer) (tz->indices + tz->timecnt);
+              tz->abbrs   = (gconstpointer) (tz->infos + typecnt);
+            }
         }
 
       if (identifier)