1 files changed, 38 insertions, 19 deletions

diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
index ed000c8..162f1df 100644
--- a/m4/stdbool.m4
+++ b/m4/stdbool.m4
@@ -1,21 +1,9 @@
 # Check for stdbool.h that conforms to C99.
 
-# Copyright (C) 2002-2003 Free Software Foundation, Inc.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-# 02111-1307, USA.
+dnl Copyright (C) 2002-2005 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.
 
 # Prepare for substituting <stdbool.h> if it is not supported.
 
@@ -40,7 +28,10 @@ AC_DEFUN([AM_STDBOOL_H],
   AC_SUBST([HAVE__BOOL])
 ])
 
-# This macro is only needed in autoconf <= 2.54.  Newer versions of autoconf
+# AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
+AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
+
+# This macro is only needed in autoconf <= 2.59.  Newer versions of autoconf
 # have this macro built-in.
 
 AC_DEFUN([AC_HEADER_STDBOOL],
@@ -59,7 +50,7 @@ AC_DEFUN([AC_HEADER_STDBOOL],
            "error: false is not 0"
           #endif
           #ifndef true
-           "error: false is not defined"
+           "error: true is not defined"
           #endif
           #if true != 1
            "error: true is not 1"
@@ -79,8 +70,36 @@ AC_DEFUN([AC_HEADER_STDBOOL],
           char g[true];
           char h[sizeof (_Bool)];
           char i[sizeof s.t];
+          enum { j = false, k = true, l = false * true, m = true * 256 };
+          _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 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
+          _Bool q = true;
+          _Bool *pq = &q;
+        ],
+        [
+          *pq |= q;
+          *pq |= ! q;
+          /* 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 + !q + !pq);
         ],
-        [ return !a + !b + !c + !d + !e + !f + !g + !h + !i; ],
         [ac_cv_header_stdbool_h=yes],
         [ac_cv_header_stdbool_h=no])])
    AC_CHECK_TYPES([_Bool])