+
+/* Bison depends on libiberty's implementation of bitsets, which
+ requires a `libiberty.h' file. This file provides the minimum
+ services. */
+
+#ifndef BISON_LIBIBERTY_H_
+# define BISON_LIBIBERTY_H_ 1
+
+# ifndef __attribute__
+# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
+# define __attribute__(x)
+# endif
+# endif
+
+# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+
+# include "xalloc.h"
+
+#endif /* ! BISON_LIBIBERTY_H_ */