Index: devel/glib20/files/patch-glib_gtimezone.c
===================================================================
--- devel/glib20/files/patch-glib_gtimezone.c	(nonexistent)
+++ devel/glib20/files/patch-glib_gtimezone.c	(working copy)
@@ -0,0 +1,44 @@
+--- glib/gtimezone.c.orig	2018-09-21 12:29:23.000000000 +0300
++++ glib/gtimezone.c	2019-09-12 00:53:42.760936000 +0300
+@@ -187,6 +187,8 @@
+ 
+ G_LOCK_DEFINE_STATIC (time_zones);
+ static GHashTable/*<string?, GTimeZone>*/ *time_zones;
++static GTimeZone *tz_utc = NULL;
++static GTimeZone *tz_local = NULL;
+ 
+ #define MIN_TZYEAR 1916 /* Daylight Savings started in WWI */
+ #define MAX_TZYEAR 2999 /* And it's not likely ever to go away, but
+@@ -264,6 +266,8 @@
+ GTimeZone *
+ g_time_zone_ref (GTimeZone *tz)
+ {
++  if (tz == NULL)
++    return NULL;
+   g_assert (tz->ref_count > 0);
+ 
+   g_atomic_int_inc (&tz->ref_count);
+@@ -1460,7 +1464,10 @@
+ GTimeZone *
+ g_time_zone_new_utc (void)
+ {
+-  return g_time_zone_new ("UTC");
++  if (tz_utc == NULL) {
++    tz_utc = g_time_zone_new ("UTC");
++  }
++  return g_time_zone_ref(tz_utc);
+ }
+ 
+ /**
+@@ -1483,7 +1490,10 @@
+ GTimeZone *
+ g_time_zone_new_local (void)
+ {
+-  return g_time_zone_new (getenv ("TZ"));
++  if (tz_local == NULL) {
++    tz_local = g_time_zone_new (getenv ("TZ"));
++  }
++  return g_time_zone_ref(tz_local);
+ }
+ 
+ #define TRANSITION(n)         g_array_index (tz->transitions, Transition, n)