Bug #1030

- Added portable implementation of timegm for non GNU/BSD platforms that
  don't have their own implementation
- Removed the use of tm_gmtoff on non GNU/BSD platforms that don't have
  it as part of the tm struct in time.h
- Added CMake tests HAVE_TIMEGM and HAVE_TM_GMTOFF

src/Nibbler.cpp

@@ -37,6 +37,7 @@
 #ifdef NIBBLER_FEATURE_REGEX
 #include <RX.h>
 #endif
+#include <cmake.h>
 
 static const char*        _uuid_pattern    = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
 static const unsigned int _uuid_min_length = 9;
@@ -701,7 +702,9 @@ bool Nibbler::getDateISO (time_t& t)
       tms.tm_hour   = hour;
       tms.tm_min    = minute;
       tms.tm_sec    = second;
+#ifdef HAVE_TM_GMTOFF
       tms.tm_gmtoff = 0;
+#endif
 
       t = timegm (&tms);
       return true;

src/util.cpp

@@ -610,3 +610,23 @@ const std::string indentProject (
 
 ////////////////////////////////////////////////////////////////////////////////
 
+////////////////////////////////////////////////////////////////////////////////
+#ifndef HAVE_TIMEGM
+time_t timegm (struct tm *tm)
+{
+  time_t ret;
+  char *tz;
+  tz = getenv ("TZ");
+  setenv ("TZ", "UTC", 1);
+  tzset ();
+  ret = mktime (tm);
+  if (tz)
+    setenv ("TZ", tz, 1);
+  else
+    unsetenv ("TZ");
+  tzset ();
+  return ret;
+}
+#endif
+////////////////////////////////////////////////////////////////////////////////
+

src/util.h

@@ -84,5 +84,9 @@ const std::string indentProject (
   const std::string& whitespace = "  ",
   char delimiter = '.');
 
+#ifndef HAVE_TIMEGM
+  time_t timegm (struct tm *tm);
+#endif
+
 #endif
 ////////////////////////////////////////////////////////////////////////////////