Index: head/sysutils/dwatch-gource/Makefile
===================================================================
--- head/sysutils/dwatch-gource/Makefile
+++ head/sysutils/dwatch-gource/Makefile
@@ -19,6 +19,12 @@
 
 OPTIONS_DEFINE=	DOCS
 
+.include <bsd.port.options.mk>
+
+.if ${OSVERSION} < 1101516 || (${OSVERSION} >= 1200000 && ${OSVERSION} < 1200065)
+IGNORE=         requires dwatch available in recent FreeBSD 11 or 12
+.endif
+
 do-install:
 	${INSTALL_SCRIPT} ${WRKSRC}/gwatch ${STAGEDIR}${PREFIX}/sbin
 	@${MKDIR} ${STAGEDIR}${PREFIX}/libexec/dwatch
Index: head/sysutils/dwatch-pwsnoop/Makefile
===================================================================
--- head/sysutils/dwatch-pwsnoop/Makefile
+++ head/sysutils/dwatch-pwsnoop/Makefile
@@ -20,6 +20,12 @@
 
 OPTIONS_DEFINE=	DOCS
 
+.include <bsd.port.options.mk>
+
+.if ${OSVERSION} < 1101516 || (${OSVERSION} >= 1200000 && ${OSVERSION} < 1200065)
+IGNORE=         requires dwatch available in recent FreeBSD 11 or 12
+.endif
+
 do-install:
 	@${MKDIR} ${STAGEDIR}${PREFIX}/libexec/dwatch
 	${INSTALL_DATA} ${WRKSRC}/pwsnoop ${STAGEDIR}${PREFIX}/libexec/dwatch