avoid redundant tzset() calls

The  tzset()  function  initializes  the tzname variable from the
TZ environment variable.

There doesn't seem to be any valid usecase of calling this redundantly.
It is an overhead that can be avoided.

In both the occurances, locatime_r() is called right afterwards, which
is documented to also perform the tzset()'s side effects.

Author: irfanHaslanded

src/tree_data_common.c

@@ -1626,9 +1626,6 @@ ly_time_tz_offset_at(time_t time)
     struct tm tm_local, tm_utc;
     int result = 0;
 
-    /* init timezone */
-    tzset();
-
     /* get local and UTC time */
     localtime_r(&time, &tm_local);
     gmtime_r(&time, &tm_utc);
@@ -1776,9 +1773,6 @@ ly_time_time2str(time_t time, const char *fractions_s, char **str)
 
     LY_CHECK_ARG_RET(NULL, str, LY_EINVAL);
 
-    /* init timezone */
-    tzset();
-
     /* convert */
     if (!localtime_r(&time, &tm)) {
         return LY_ESYS;