diff --git a/libbacktrace/ChangeLog b/libbacktrace/ChangeLog
index 0cf79cf4a40d..5e89df42ce0c 100644
--- a/libbacktrace/ChangeLog
+++ b/libbacktrace/ChangeLog
@@ -1,3 +1,7 @@
+2012-09-18  Ian Lance Taylor  <iant@google.com>
+
+	* dwarf.c: Correct test of HAVE_DECL_STRNLEN.
+
 2012-09-18  Ian Lance Taylor  <iant@google.com>
 
 	* configure.ac: Add AC_USE_SYSTEM_EXTENSIONS.
diff --git a/libbacktrace/dwarf.c b/libbacktrace/dwarf.c
index 34861fce484a..43fb931da168 100644
--- a/libbacktrace/dwarf.c
+++ b/libbacktrace/dwarf.c
@@ -44,7 +44,7 @@ POSSIBILITY OF SUCH DAMAGE.  */
 #include "backtrace.h"
 #include "internal.h"
 
-#ifndef HAVE_DECL_STRNLEN
+#if !defined(HAVE_DECL_STRNLEN) || !HAVE_DECL_STRNLEN
 /* The function is defined in libiberty if needed.  */
 extern size_t strnlen (const char *, size_t);
 #endif