diff --git a/ChangeLog b/ChangeLog
index af0f15b468..cadf8613f3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2018-10-08  Paul Eggert  <eggert@cs.ucla.edu>
+
+	mktime fix for Gnulib + coreutils
+	[BZ#23745]
+	This fix affects only Gnulib.  Problem discovered when
+	mktime.c was used as part of Gnulib in bleeding-edge Coreutils.
+	* time/mktime.c:
+	(my_tzset) [!_LIBC && !NEED_MKTIME_WORKING && !NEED_MKTIME_WINDOWS]:
+	Do not define since it is not used.  Defining an unused static
+	function prompts a warning from GCC when Coreutils is configured
+	with --enable-gcc-warnings.
+
 2018-10-08  Leonardo Sandoval  <leonardo.sandoval.gonzalez@intel.com>
 
 	* benchtests/scripts/compare_bench.py (main): set float type on
diff --git a/time/mktime.c b/time/mktime.c
index 1404ee9f1f..00f0dec6b4 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -78,7 +78,7 @@
 
 #include "mktime-internal.h"
 
-#ifndef _LIBC
+#if !defined _LIBC && (NEED_MKTIME_WORKING || NEED_MKTIME_WINDOWS)
 static void
 my_tzset (void)
 {