(AC_HEADER_STDBOOL): Add some comments.

diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
index 162f1dfc80ced56fe1bd87b2acf77897bf6bc9a5..9d423d9d1fe3b1d18ed977ec5f5f622dbdcbda90 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.
@@ -77,7 +77,7 @@ AC_DEFUN([AC_HEADER_STDBOOL],
          #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>.
+             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.
@@ -86,10 +86,17 @@ AC_DEFUN([AC_HEADER_STDBOOL],
              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.  */
+             our stdbool.h substitute should suffice.  We also test
+             this with GCC, where it should work, to detect more
+             quickly whether someone messes up the test in the
+             future.  */
           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;
        ],