--- a/src/auto/configure
+++ b/src/auto/configure
@@ -10362,6 +10362,56 @@ fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
+{ $as_echo "$as_me:$LINENO: checking whether __attribute__((unused)) is allowed" >&5
+$as_echo_n "checking whether __attribute__((unused)) is allowed... " >&6; }
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <stdio.h>
+int
+main ()
+{
+int x __attribute__((unused));
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+  { $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }; cat >>confdefs.h <<\_ACEOF
+#define HAVE_ATTRIBUTE_UNUSED 1
+_ACEOF
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
 if test "${ac_cv_header_elf_h+set}" = set; then
   { $as_echo "$as_me:$LINENO: checking for elf.h" >&5
 $as_echo_n "checking for elf.h... " >&6; }