diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index cf5d836f325..4fc63fa5b1a 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-08  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* acinclude.m4 ([GLIBCXX_ENABLE_C99]): Avoid -Wwrite-strings warning.
+	* configure: Regenerate.
+
 2014-05-07  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/61023
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 437221f3ab1..cbce2ae4e5b 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -1052,8 +1052,8 @@ AC_DEFUN([GLIBCXX_ENABLE_C99], [
 	vscanf("%i", args);
 	vsnprintf(fmt, 0, "%i", args);
 	vsscanf(fmt, "%i", args);
-      }],
-     [snprintf("12", 0, "%i");],
+	snprintf(fmt, 0, "%i");
+      }], [],
      [glibcxx_cv_c99_stdio=yes], [glibcxx_cv_c99_stdio=no])
   ])
   AC_MSG_RESULT($glibcxx_cv_c99_stdio)
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 9b842c70937..c481db6028b 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -16900,11 +16900,12 @@ else
 	vscanf("%i", args);
 	vsnprintf(fmt, 0, "%i", args);
 	vsscanf(fmt, "%i", args);
+	snprintf(fmt, 0, "%i");
       }
 int
 main ()
 {
-snprintf("12", 0, "%i");
+
   ;
   return 0;
 }
@@ -16930,11 +16931,12 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 	vscanf("%i", args);
 	vsnprintf(fmt, 0, "%i", args);
 	vsscanf(fmt, "%i", args);
+	snprintf(fmt, 0, "%i");
       }
 int
 main ()
 {
-snprintf("12", 0, "%i");
+
   ;
   return 0;
 }