[glib: 1/2] gtimezone: port to tzcode 2014c

[Philip Withnall <pwithnall src gnome org>]

commit 137dd7789b870be7c5acc2e1dcdbb1f44442b8b1
Author: Paul Eggert <eggert cs ucla edu>
Date:   Mon May 28 20:15:04 2018 -0700

    gtimezone: port to tzcode 2014c
    
    Problem reported by Marien Zwart in:
    https://gitlab.gnome.org/GNOME/glib/issues/878
    Derived from a fix by John Ralls proposed in that bug report.

 glib/gtimezone.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/glib/gtimezone.c b/glib/gtimezone.c
index 72a4916ad..b3220dc35 100644
--- a/glib/gtimezone.c
+++ b/glib/gtimezone.c
@@ -1677,7 +1677,10 @@ interval_end (GTimeZone *tz,
               guint      interval)
 {
   if (tz->transitions && interval < tz->transitions->len)
-    return (TRANSITION(interval)).time - 1;
+    {
+      gint64 lim = (TRANSITION(interval)).time;
+      return lim - (lim != G_MININT64);
+    }
   return G_MAXINT64;
 }