Check against AIX and HP-UX C compiler bugs.

diff --git a/m4/ChangeLog b/m4/ChangeLog
index 5d6acdc1d3f73879350c17e020c6274628fd0969..13ac8a10a5a66f1aaa28aae6731c1c80e3313a64 100644 (file)
--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,8 @@
+2006-01-24  Bruno Haible  <bruno@clisp.org>
+
+       * stdbool.m4 (AC_HEADER_STDBOOL): Check for IBM and HP-UX bugs.
+       Patch by Paul Eggert.
+
 2006-01-24  Jim Meyering  <jim@meyering.net>
 
        * openat.m4 (gl_FUNC_OPENAT): Add AC_LIBSOURCES([intprops.h]).

diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
index dcb57935395072524d674e324aa33fa182540f77..f37f27b97332e8fe2d5f1d91296639de3410cd8e 100644 (file)
--- a/m4/stdbool.m4
+++ b/m4/stdbool.m4
@@ -1,6 +1,6 @@
 # Check for stdbool.h that conforms to C99.
 
-dnl Copyright (C) 2002-2005 Free Software Foundation, Inc.
+dnl Copyright (C) 2002-2006 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -74,6 +74,28 @@ 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__
+          /* 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 cross-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
+         /* Catch a bug in an HP-UX C compiler.  See
+            http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
+            http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
+          */
+         _Bool q = true;
+         _Bool *pq = &q;
        ],
        [
          /* Refer to every declared value, to avoid compiler optimizations.  */