Merge changes from gnulib. This was prompted because the CVS

snapshot of Bison didn't build on Solaris 7 due to strnlen problems.

src/system.h

@@ -183,23 +183,7 @@ void *memrchr (const void *str, int ch, size_t size);
 | Booleans.  |
 `-----------*/
 
-#if HAVE_STDBOOL_H
-# include <stdbool.h>
-#else
-# ifndef __bool_true_false_are_defined
-#  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
-#endif
+#include <stdbool.h>
 
 
 /*-----------.