--- Gnu-Mach/device/cirbuf.c	2020/09/02 04:47:53	1.1.1.3
+++ Gnu-Mach/device/cirbuf.c	2020/09/02 04:50:07	1.1.1.4
@@ -42,6 +42,8 @@
 /* if c_cl == c_cf - 1, buffer is full */
 
 #if	DEBUG
+#include <mach/boolean.h>
+
 boolean_t cb_check_enable = FALSE;
 #define	CB_CHECK(cb) if (cb_check_enable) cb_check(cb)