Start using the bool type

This adds the bool type compatible with the C99 one, or uses it if
found.  The sources will soon be converted to use this type
consistently.

ChangeLog:
2005-06-22  Hrvoje Niksic  <[email protected]>

	* configure.in: Check for C99 conformant stdbool.h.

src/ChangeLog:
2005-06-22  Hrvoje Niksic  <[email protected]>

	* sysdep.h: Include the stdbool.h/_Bool/bool blurb from Autoconf.

Index: configure.in
===================================================================
--- configure.in	(revision 1743)
+++ configure.in	(working copy)
@@ -162,6 +162,7 @@
 dnl This is because Autoconf default includes check for STDC_HEADERS,
 dnl HAVE_SYS_TYPES_H, etc. before including them.
 AC_HEADER_STDC
+AC_HEADER_STDBOOL
 AC_CHECK_HEADERS(sys/types.h sys/stat.h)
 dnl Now check for the others.
 AC_CHECK_HEADERS(string.h strings.h limits.h unistd.h sys/time.h)
Index: src/sysdep.h
===================================================================
--- src/sysdep.h	(revision 1743)
+++ src/sysdep.h	(working copy)
@@ -63,6 +63,24 @@
 # include <io.h>
 #endif /* __WATCOMC__ */
 
+/* Provide support for C99-type boolean type "bool".  This blurb comes
+   straight from the Autoconf 2.59 manual. */
+#if HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# if ! HAVE__BOOL
+#  ifdef __cplusplus
+typedef bool _Bool;
+#  else
+typedef unsigned char _Bool;
+#  endif
+# endif
+# define bool _Bool
+# define false 0
+# define true 1
+# define __bool_true_false_are_defined 1
+#endif
+
 /* Needed for compilation under OS/2: */
 #ifdef __EMX__
 # ifndef S_ISLNK