unbreak some builds with USETOOLS=no

[coypu%sdf.org@localhost]

since bsd.hostinit.mk is not installed, building stuff using
bsd.hostprog.mk without netbsd tools isn't possible.

Also, EXTERNAL_TOOLCHAIN is not defined e.g. if using
cd src/external/bsd/nvi; make USETOOLS=no.

attached patch fixes it.
thoughts?

Index: share/mk/Makefile
===================================================================
RCS file: /cvsroot/src/share/mk/Makefile,v
retrieving revision 1.49
diff -u -r1.49 Makefile
--- share/mk/Makefile	16 Jan 2014 01:15:33 -0000	1.49
+++ share/mk/Makefile	28 May 2018 05:06:01 -0000
@@ -8,9 +8,9 @@
 .if ${MKSHARE} != "no"
 FILES=	bsd.README bsd.buildinstall.mk bsd.clang-analyze.mk bsd.clean.mk \
 	bsd.dep.mk bsd.doc.mk bsd.endian.mk bsd.files.mk bsd.gcc.mk \
-	bsd.host.mk bsd.hostlib.mk bsd.hostprog.mk bsd.inc.mk bsd.info.mk \
-	bsd.init.mk bsd.ioconf.mk bsd.kernobj.mk bsd.kinc.mk bsd.klinks.mk \
-	bsd.kmodule.mk bsd.lib.mk bsd.links.mk bsd.lua.mk \
+	bsd.host.mk bsd.hostinit.mk bsd.hostlib.mk bsd.hostprog.mk bsd.inc.mk \
+	bsd.info.mk bsd.init.mk bsd.ioconf.mk bsd.kernobj.mk bsd.kinc.mk \
+	bsd.klinks.mk bsd.kmodule.mk bsd.lib.mk bsd.links.mk bsd.lua.mk \
 	bsd.man.mk bsd.nls.mk \
 	bsd.obj.mk bsd.own.mk bsd.prog.mk bsd.rpc.mk bsd.shlib.mk \
 	bsd.subdir.mk bsd.sys.mk bsd.syscall.mk bsd.test.mk bsd.x11.mk sys.mk
Index: share/mk/bsd.hostprog.mk
===================================================================
RCS file: /cvsroot/src/share/mk/bsd.hostprog.mk,v
retrieving revision 1.80
diff -u -r1.80 bsd.hostprog.mk
--- share/mk/bsd.hostprog.mk	4 May 2018 14:50:40 -0000	1.80
+++ share/mk/bsd.hostprog.mk	28 May 2018 05:06:01 -0000
@@ -92,7 +92,7 @@
 MKDEP:=		${HOST_MKDEP}
 MKDEPCXX:=	${HOST_MKDEPCXX}
 
-.if ${TOOLCHAIN_MISSING} == "no" || defined(EXTERNAL_TOOLCHAIN)
+.if ${TOOLCHAIN_MISSING:Uno} == "no" || defined(EXTERNAL_TOOLCHAIN)
 OBJHOSTMACHINE=	# set
 .endif
 
Index: distrib/sets/lists/base/mi
===================================================================
RCS file: /cvsroot/src/distrib/sets/lists/base/mi,v
retrieving revision 1.1175
diff -u -r1.1175 mi
--- distrib/sets/lists/base/mi	23 May 2018 01:05:47 -0000	1.1175
+++ distrib/sets/lists/base/mi	28 May 2018 05:06:06 -0000
@@ -4784,6 +4784,7 @@
 ./usr/share/mk/bsd.files.mk			base-mk-share		share
 ./usr/share/mk/bsd.gcc.mk			base-mk-share		share
 ./usr/share/mk/bsd.host.mk			base-mk-share		share
+./usr/share/mk/bsd.hostinit.mk			base-mk-share		share
 ./usr/share/mk/bsd.hostlib.mk			base-mk-share		share
 ./usr/share/mk/bsd.hostprog.mk			base-mk-share		share
 ./usr/share/mk/bsd.inc.mk			base-mk-share		share