share/termcap requires ex from usr.bin/vi in order to compile, and since usr.bin

comes after share in SUBDIR in Makefile.inc1, the build will fail when vi is not
installed on the build host

Run build-tools for usr.bin/vi and install ex, etc to WORLDTMP to enable building
share/termcap on hosts that don't have nvi installed on them

Makefile.inc1

@@ -271,7 +271,9 @@ TMAKE=		MAKEOBJDIRPREFIX=${OBJTREE} \
 		BOOTSTRAPPING=${OSRELDATE} \
 		SSP_CFLAGS= \
 		-DNO_LINT \
-		-DNO_CPU_CFLAGS MK_WARNS=no MK_CTF=no MK_CLANG_FULL=no MK_LLDB=no MK_TESTS=no
+		-DNO_CPU_CFLAGS \
+		MK_WARNS=no MK_CTF=no MK_CLANG_FULL=no MK_LLDB=no MK_MAN=no \
+		MK_SHAREDOCS=no MK_TESTS=no
 
 # cross-tools stage
 XMAKE=		TOOLS_PREFIX=${WORLDTMP} ${BMAKE} \
@@ -1386,6 +1388,14 @@ build-tools: .MAKE
 		${MAKE} DIRPRFX=${_tool}/ depend && \
 		${MAKE} DIRPRFX=${_tool}/ all
 .endfor
+.for _tool in \
+    usr.bin/vi
+	${_+_}@${ECHODIR} "===> ${_tool} (obj,build-tools,install)"; \
+		cd ${.CURDIR}/${_tool} && \
+		${MAKE} DIRPRFX=${_tool}/ obj && \
+		${MAKE} DIRPRFX=${_tool}/ build-tools DESTDIR=${WORLDTMP}/ \
+		MK_MAN=no
+.endfor
 
 #
 # kernel-tools: Build kernel-building tools

usr.bin/vi/Makefile

@@ -77,4 +77,9 @@ SRCS+=	vs_line.c vs_msg.c vs_refresh.c vs_relative.c vs_smap.c vs_split.c
 # Wide char regex
 SRCS+=	regcomp.c regerror.c regexec.c regfree.c
 
+build-tools:
+.for t in obj depend all install
+	cd ${.CURDIR} && ${MAKE} $t SUBDIR=
+.endfor
+
 .include <bsd.prog.mk>