https://bugs.gentoo.org/943846
--- a/libinit.h
+++ b/libinit.h
@@ -107,7 +107,11 @@
 #define  DEFPIDEXT ".pid"
 #define  DEFPIDLEN 14		/* The string length of /var/run/.pid + 1 */
 
+#if __STDC_VERSION__ <= 201710L
 typedef enum _boolean {false, true} boolean;
+#else
+typedef bool boolean;
+#endif
 
 extern char **environ;
 extern char     * newenvp[];