diff --git a/configure.ac b/configure.ac
index 0fd1364..c6cb4bc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -129,7 +129,7 @@
       #include <time.h>
     ], [
       struct tm tm;
-      tm.tm_zone = 1;
+      tm.tm_zone = (char*)"UTC";
     ])],
     [ac_cv_struct_tm_zone=yes],
     [ac_cv_struct_tm_zone=no]