check_c_source_compiles("
#include <sys/types.h>
#include <sys/time.h>
#include <time.h>
int main(void) {
    struct tm t;
    (void) t.tm_gmtoff; /* try to actually use it */
    return 0;
}
" SYSLOG_NG_HAVE_STRUCT_TM_TM_GMTOFF)