https://bugs.gentoo.org/944450

--- a/sys-defines.h
+++ b/sys-defines.h
@@ -166,17 +166,7 @@ extern __C_LINKAGE void free (void * ptr);
 /* Support the `bool' datatype, which our code uses extensively.          */
 /**************************************************************************/
 
-#ifndef __cplusplus
-#ifndef HAVE_BOOL_IN_CC
-#ifdef __STDC__
-typedef enum { false = 0, true = 1 } bool;
-#else  /* not __STDC__, do things the old-fashioned way */
-typedef int bool;
-#define false 0
-#define true 1
-#endif
-#endif /* not HAVE_BOOL_IN_CC */
-#endif /* not __cplusplus */
+#include <stdbool.h>
   
 /**************************************************************************/
 /* Define numerical constants (unofficial, so may not be in math.h).      */