Tweak the code to make it more reusable.

diff --git a/m4/ChangeLog b/m4/ChangeLog
index 4e60082379831bd7b5136be381205527545f63a9..4f947dceaa0271def97d5b10b92d1dd48797fdd6 100644 (file)
--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,8 @@
+2005-10-17  Bruno Haible  <bruno@clisp.org>
+
+       * stdbool.m4 (AC_HEADER_STDBOOL): Change the return statement so that
+       it can also be used in a test.
+
 2005-10-11  Simon Josefsson  <jas@extundo.com>
 
        * md5.m4: Remove call to uint32_t.m4.

diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
index 922a00258ee03299cb8cc9463d7c37e88a6cc7b1..dcb57935395072524d674e324aa33fa182540f77 100644 (file)
--- a/m4/stdbool.m4
+++ b/m4/stdbool.m4
@@ -76,7 +76,8 @@ AC_DEFUN([AC_HEADER_STDBOOL],
          char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
        ],
        [
-         return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !j + !k + !l
+         /* Refer to every declared value, to avoid compiler optimizations.  */
+         return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
                  + !m + !n + !o + !p);
        ],
        [ac_cv_header_stdbool_h=yes],