Bug in AC_VAR_TIMEZONE_EXTERNALS

[Laurent Rineau]

On FreeBSD, timezone is a function:

   char *timezone(int, int);

and the test AC_VAR_TIMEZONE_EXTERNALS returns with success whereas 
timezone is not a variable of type compatible with time_t.

I patched it. I transformed:
 AC_TRY_LINK([#include <time.h>], [return (int)timezone;],
to:
 AC_TRY_LINK([#include <time.h>], [return (int)( 0 - timezone );],

Perhaps something less stupid, such as:
 [ time_t t = timezone; ]
should be used.

(Please reply to me as well as to the list, because I am not member of 
the list.)

--
Laurent Rineau