Checking at configure time for timezone integer variable.

acinclude.m4

@@ -198,3 +198,15 @@ dnl For debugging only
  
 ])
 
+dnl LIBBURNIA_TRY_TIMEZONE is by Thomas Schmitt, libburnia project
+dnl It tests whether the global variable exists and is suitable for
+dnl integer arithmetics.
+AC_DEFUN([LIBBURNIA_TRY_TIMEZONE],
+[
+    echo -n "checking for timezone variable ... "
+    AC_TRY_LINK([ #include <time.h> ], [long int i; i = 1 - timezone; ], 
+                [LIBBURNIA_TIMEZONE="timezone"], [LIBBURNIA_TIMEZONE="0"]
+    )
+    echo "$LIBBURNIA_TIMEZONE"
+])
+

configure.ac

@@ -114,6 +114,16 @@ AC_CHECK_DECL([timegm],
 	,
 	[#include <time.h>])
 
+dnl Whether timezone is an integer variable
+AH_TEMPLATE([Libburnia_timezonE], [Either timezone or 0])
+LIBBURNIA_TRY_TIMEZONE
+if test x$LIBBURNIA_TIMEZONE = xtimezone
+then
+   AC_DEFINE([Libburnia_timezonE], [timezone])
+else
+   AC_DEFINE([Libburnia_timezonE], [0])
+fi
+
 dnl Check if non standard eaccess() function is available
 AC_CHECK_DECL([eaccess], 
 	[AC_DEFINE(HAVE_EACCESS, 1, [Define this if eaccess function is available])],

libisofs/util.c

@@ -1574,7 +1574,10 @@ void iso_datetime_7(unsigned char *buf, time_t t, int always_gmt)
 #else
     if (tm.tm_isdst < 0)
         tm.tm_isdst = 0;
-    tzoffset = ( - timezone / 60 / 15 ) + 4 * tm.tm_isdst;
+#ifndef Libburnia_timezonE
+#define Libburnia_timezonE timezone
+#endif
+    tzoffset = ( - Libburnia_timezonE / 60 / 15 ) + 4 * tm.tm_isdst;
 #endif
 
     if (tzoffset > 52 || tzoffset < -48 || always_gmt) {