(AC_HEADER_STDBOOL): Add an "#ifdef __xlc__" test,

since yesterday's attempt didn't work.

diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
index 945a036..8893d0b 100644 (file)
--- a/m4/stdbool.m4
+++ b/m4/stdbool.m4
@@ -71,6 +71,22 @@ AC_DEFUN([AC_HEADER_STDBOOL],
          _Bool n[m];
          char o[sizeof n == m * sizeof n[0] ? 1 : -1];
          char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
+         #if defined __xlc__ || __GNUC__
+          /* Catch a bug in IBM AIX xlc compiler version 6.0.0.0
+             reported by James Lemley on 2005-10-05; see
+             <http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html>.
+             This test is not quite right, since xlc is allowed to
+             reject this program, as the initializer for xlcbug is
+             not one of the forms that C requires support for.
+             However, doing the test right would require a run-time
+             test, and that would make crosss-compilation harder.
+             Let us hope that IBM fixes the xlc bug, and also adds
+             support for this kind of constant expression.  In the
+             meantime, this test will reject xlc, which is OK, since
+             our stdbool.h substitute should suffice.  */
+          char digs[] = "0123456789";
+          int xlcbug = 1 / (&(digs + 5)[-2 + (bool) 1] == &digs[4] ? 1 : -1);
+         #endif
        ],
        [
          return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !j + !k + !l