+/*************************************************
+* Timezone environment flipping *
+*************************************************/
+
+static uschar *
+to_tz(uschar * tz)
+{
+uschar * old = US getenv("TZ");
+(void) setenv("TZ", CCS tz, 1);
+tzset();
+return old;
+}
+
+static void
+restore_tz(uschar * tz)
+{
+if (tz)
+ (void) setenv("TZ", CCS tz, 1);
+else
+ (void) os_unsetenv(US"TZ");
+tzset();
+}
+