Fix the tz detection code.

source/common/putilimp.h

 /*
 ******************************************************************************
 *
 *   Copyright (C) 1997-2014, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************
 *
 *  FILE NAME : putilimp.h
 *
@@ skipping 465 matching lines @@
  *   tzname(0)  Three-letter time-zone name derived from TZ environment
  *              variable. E.g., "PST".
  *   tzname(1)  Three-letter DST zone name derived from TZ environment
  *              variable.  E.g., "PDT". If DST zone is omitted from TZ,
  *              tzname(1) is an empty string.
  * @internal
  */
 U_INTERNAL const char* U_EXPORT2 uprv_tzname(int n);
 
 /**
+ * Reset the global tzname cache.
+ * @internal
+ */
+U_INTERNAL void uprv_tzname_clear_cache();
+
+/**
  * Get UTC (GMT) time measured in milliseconds since 0:00 on 1/1/1970.
  * This function is affected by 'faketime' and should be the bottleneck for all user-visible ICU time functions.
  * @return the UTC time measured in milliseconds
  * @internal
  */
 U_INTERNAL UDate U_EXPORT2 uprv_getUTCtime(void);
 
 /**
  * Get UTC (GMT) time measured in milliseconds since 0:00 on 1/1/1970.
  * This function is not affected by 'faketime', so it should only be used by low level test functions- not by anything that
@@ skipping 106 matching lines @@
 /* also _C_TS_calloc(x) */
 #else
 /* C defaults */
 # define uprv_default_malloc(x) malloc(x)
 # define uprv_default_realloc(x,y) realloc(x,y)
 # define uprv_default_free(x) free(x)
 #endif
 
 
 #endif