diff --git a/share/mk/local.dirdeps.mk b/share/mk/local.dirdeps.mk
--- a/share/mk/local.dirdeps.mk
+++ b/share/mk/local.dirdeps.mk
@@ -60,7 +60,17 @@
 	rm -rf ${OBJTOP}/tmp
 beforedirdeps: cleanup_worldtmp
 .endif
+
+# pseudo option for building host tools on old or non-FreeBSD host
+# allows us to leverage Makefile.depend.options with
+# DIRDEPS_OPTIONS = host_egacy
+.if ${.MAKE.OS} != "FreeBSD" || ${_HOST_OSREL:R} < ${OS_REVISION:R}
+MK_host_egacy.host= yes
 .endif
+# this will apply otherwise
+MK_host_egacy= no
+
+.endif				# !target(_DIRDEP_USE)
 
 # reset this each time
 DIRDEPS_FILTER.xtras=
@@ -71,6 +81,7 @@
 .if ${DEP_MACHINE} != "host"
 
 # this is how we can handle optional dependencies
+# actually Makefile.depend.options is better
 .if ${DEP_RELDIR} == "lib/libc"
 DIRDEPS += lib/libc_nonshared
 .if ${MK_SSP:Uno} != "no" 
diff --git a/share/mk/local.init.mk b/share/mk/local.init.mk
--- a/share/mk/local.init.mk
+++ b/share/mk/local.init.mk
@@ -19,7 +19,8 @@
 CXXFLAGS_LAST+= --sysroot=${SYSROOT}
 LDADD+= --sysroot=${SYSROOT}
 .elif ${MK_STAGING} == "yes"
-CFLAGS+= -isystem ${STAGE_INCLUDEDIR}
+ISYSTEM?= ${STAGE_INCLUDEDIR}
+CFLAGS+= -isystem${ISYSTEM}
 # XXX: May be needed for GCC to build with libc++ rather than libstdc++. See Makefile.inc1
 #CXXFLAGS+= -std=gnu++11
 #LDADD+= -L${STAGE_LIBDIR}/libc++
@@ -38,4 +39,8 @@
 .-include "src.init.mk"
 .-include <site.init.mk>
 .-include "${.CURDIR}/local.init.mk"
+
+.if !empty(HAVE_FLAGS)
+CFLAGS+= ${HAVE_FLAGS:U:@F@-D${F}=${$F:U1}@}
+.endif
 .endif
diff --git a/share/mk/src.init.linux.mk b/share/mk/src.init.linux.mk
new file mode 100644
--- /dev/null
+++ b/share/mk/src.init.linux.mk
@@ -0,0 +1,33 @@
+# We want to build some host tools (eg makefs, mkimg) for Linux
+
+.if ${MACHINE:Nhost*} == ""
+
+CFLAGS+= -I${SRCTOP}/tools/build/cross-build/include/linux
+
+WARNS= 0
+
+CFLAGS+= -DEFTYPE=EINVAL
+
+.ifdef PROG
+LOCAL_LIBRARIES+= bsd egacy
+LIBADD+= egacy m
+# static linking does not work
+NO_SHARED= no
+.endif
+
+MK_TESTS= no
+MK_MAN= no
+
+# override some HAVE_FLAGS
+HAVE_STRUCT_STAT_ST_FLAGS= 0
+
+# someone used __unused for struct padding on Linux
+# we don't care enough about linux/sysctl.h to work around it
+CFLAGS+= -D__unused= -D_LINUX_SYSCTL_H
+
+# avoid type conflicts
+CFLAGS+= -D__va_list=__builtin_va_list
+
+CFLAGS+= -D_DEFAULT_SOURCE -D_GNU_SOURCE -D_XOPEN_SOURCE
+
+.endif
diff --git a/share/mk/src.init.mk b/share/mk/src.init.mk
--- a/share/mk/src.init.mk
+++ b/share/mk/src.init.mk
@@ -8,4 +8,20 @@
 	${_+_}@env BUILDENV_DIR=${.CURDIR} ${MAKE} -C ${SRCTOP} buildenv
 .endif
 
+.if ${MACHINE:Nhost*} == ""
+.-include <src.init.${.MAKE.OS:tl}.mk>
+
+.if ${.MAKE.OS} == "FreeBSD" && ${_HOST_OSREL:R} < ${OS_REVISION:R}
+.ifdef PROG
+LOCAL_LIBRARIES+= egacy
+LIBADD+= egacy
+.endif
+.endif
+
+.if ${MK_STAGING} == "yes"
+ISYSTEM=	/usr/include
+CFLAGS+=	-I${STAGE_INCLUDEDIR}
+.endif
+.endif
+
 .endif	# !target(__<src.init.mk>__)
diff --git a/share/mk/src.sys.env.mk b/share/mk/src.sys.env.mk
--- a/share/mk/src.sys.env.mk
+++ b/share/mk/src.sys.env.mk
@@ -24,7 +24,7 @@
 RELSRCTOP?=	${RELTOP}
 
 .if !defined(OS_REVISION)
-OS_REVISION!=eval `sh ${SRCTOP}/sys/conf/newvers.sh -V REVISION` && echo $$REVISION || echo
+OS_REVISION!=eval `sh ${SRCTOP}/sys/conf/newvers.sh -V REVISION 2> /dev/null` && echo $$REVISION || echo
 .export OS_REVISION
 .endif