--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m4/stdbool.m4	Fri Jul 23 17:18:52 2010 -0600
@@ -0,0 +1,115 @@
+# Check for stdbool.h that conforms to C99.
+
+dnl Copyright (C) 2002-2006, 2009-2010 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.
+
+AC_DEFUN([AM_STDBOOL_H],
+[
+  AC_REQUIRE([AC_HEADER_STDBOOL])
+
+  # Define two additional variables used in the Makefile substitution.
+
+  if test "$ac_cv_header_stdbool_h" = yes; then
+    STDBOOL_H=''
+  else
+    STDBOOL_H='stdbool.h'
+  fi
+  AC_SUBST([STDBOOL_H])
+
+  if test "$ac_cv_type__Bool" = yes; then
+    HAVE__BOOL=1
+  else
+    HAVE__BOOL=0
+  fi
+  AC_SUBST([HAVE__BOOL])
+])
+
+# 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],
+  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
+     [ac_cv_header_stdbool_h],
+     [AC_TRY_COMPILE(
+        [
+          #include <stdbool.h>
+          #ifndef bool
+           "error: bool is not defined"
+          #endif
+          #ifndef false
+           "error: false is not defined"
+          #endif
+          #if false
+           "error: false is not 0"
+          #endif
+          #ifndef true
+           "error: true is not defined"
+          #endif
+          #if true != 1
+           "error: true is not 1"
+          #endif
+          #ifndef __bool_true_false_are_defined
+           "error: __bool_true_false_are_defined is not defined"
+          #endif
+
+          struct s { _Bool s: 1; _Bool t; } s;
+
+          char a[true == 1 ? 1 : -1];
+          char b[false == 0 ? 1 : -1];
+          char c[__bool_true_false_are_defined == 1 ? 1 : -1];
+          char d[(bool) 0.5 == true ? 1 : -1];
+          bool e = &s;
+          char f[(_Bool) 0.0 == false ? 1 : -1];
+          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__ || defined __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.  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;
+        ],
+        [
+          *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);
+        ],
+        [ac_cv_header_stdbool_h=yes],
+        [ac_cv_header_stdbool_h=no])])
+   AC_CHECK_TYPES([_Bool])
+   if test $ac_cv_header_stdbool_h = yes; then
+     AC_DEFINE([HAVE_STDBOOL_H], [1], [Define to 1 if stdbool.h conforms to C99.])
+   fi])