Adjust tzset() implementation to better follow the POSIX specs and

make some more perl tests happy.
* no longer expect a ICU timezone ID in the TZ environment variable,
  but only expect this format if the TZ-value is starting with ':'
* accept "standard" TZ-values like "EST5" (of which only "EST" is
  relevant to us) - if such a value is specified, we hardcode the
  timezone name to the given value, no matter how ICU calls it
* adjust tests accordingly


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39415 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/libroot/locale/ICULocaleBackend.h

@@ -45,7 +45,7 @@ public:
 	virtual status_t			Strxfrm(char* out, const char* in, size_t size,
 									size_t& outSize);
 
-	virtual status_t			TZSet(const char* timeZoneID);
+	virtual status_t			TZSet(const char* timeZoneID, const char* tz);
 	virtual	status_t			Localtime(const time_t* inTime,
 									struct tm* tmOut);
 	virtual status_t			Gmtime(const time_t* inTime, struct tm* tmOut);

headers/private/libroot/locale/ICUTimeConversion.h

@@ -25,7 +25,7 @@ public:
 	virtual void				Initialize(
 									TimeConversionDataBridge* dataBridge);
 
-			status_t			TZSet(const char* timeZoneID);
+			status_t			TZSet(const char* timeZoneID, const char* tz);
 
 			status_t			Localtime(const time_t* inTime,
 									struct tm* tmOut);

headers/private/libroot/locale/LocaleBackend.h

@@ -127,7 +127,8 @@ public:
 	virtual status_t			Strxfrm(char* out, const char* in, size_t size,
 									size_t& outSize) = 0;
 
-	virtual status_t			TZSet(const char* timeZoneID) = 0;
+	virtual status_t			TZSet(const char* timeZoneID,
+									const char* tz) = 0;
 	virtual	status_t			Localtime(const time_t* inTime,
 									struct tm* tmOut) = 0;
 	virtual	status_t			Gmtime(const time_t* inTime,