By default the mkioctl program that generates code for kdump does look for
ioctls in the whole /usr/include tree, but this does break when xorg is merged.
This patch allows to look for include files only in the source tree.

Index: fbsd-6/usr.bin/kdump/Makefile
===================================================================
--- fbsd-6.orig/usr.bin/kdump/Makefile
+++ fbsd-6/usr.bin/kdump/Makefile
@@ -10,6 +10,6 @@ CFLAGS+=	-I${.CURDIR}/../ktrace -I${.CUR
 CLEANFILES=	ioctl.c
 
 ioctl.c: mkioctls
-	sh ${.CURDIR}/mkioctls ${DESTDIR}/usr/include > ${.TARGET}
+	sh ${.CURDIR}/mkioctls ${.CURDIR}/../../include > ${.TARGET}
 
 .include <bsd.prog.mk>
Index: fbsd-6/usr.bin/truss/Makefile
===================================================================
--- fbsd-6.orig/usr.bin/truss/Makefile
+++ fbsd-6/usr.bin/truss/Makefile
@@ -29,6 +29,6 @@ syscalls.h:	syscalls.master
 		${.CURDIR}/i386.conf
 
 ioctl.c: ${.CURDIR}/../kdump/mkioctls
-	sh ${.CURDIR}/../kdump/mkioctls ${DESTDIR}/usr/include > ${.TARGET}
+	sh ${.CURDIR}/../kdump/mkioctls ${.CURDIR}/../../include > ${.TARGET}
 
 .include <bsd.prog.mk>