diff --git a/ChangeLog b/ChangeLog
index fca05a527c2..1cb5ed3585f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2012-07-11  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* configure.ac (tzset): Remove check that's redundant with gnulib.
+
 2012-07-11  Glenn Morris  <rgm@gnu.org>
 
 	* configure.ac (CLASH_DETECTION): Define unconditionally.
diff --git a/configure.ac b/configure.ac
index 82201318515..e55c40fe77c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3021,7 +3021,7 @@ AC_SUBST(KRB5LIB)
 AC_SUBST(DESLIB)
 AC_SUBST(KRB4LIB)
 
-AC_CHECK_FUNCS(tzset)
+AC_CHECK_FUNCS_ONCE(tzset)
 AC_MSG_CHECKING(whether localtime caches TZ)
 AC_CACHE_VAL(emacs_cv_localtime_cache,
 [if test x$ac_cv_func_tzset = xyes; then