Index: sys/cddl/boot/zfs/zfsimpl.h
===================================================================
--- sys/cddl/boot/zfs/zfsimpl.h
+++ sys/cddl/boot/zfs/zfsimpl.h
@@ -76,7 +76,9 @@
 #define	AVL_PCMP(a, b)	\
 	(((uintptr_t)(a) > (uintptr_t)(b)) - ((uintptr_t)(a) < (uintptr_t)(b)))
 
+#ifndef NEED_SOLARIS_BOOLEAN	/* Only defined when we'll define this elsewhere */
 typedef enum { B_FALSE, B_TRUE } boolean_t;
+#endif
 
 /* CRC64 table */
 #define	ZFS_CRC64_POLY	0xC96C5795D7870F42ULL	/* ECMA-182, reflected form */