Fix native-xtools breakage when building a gcc enabled target on a clang

enabled host.  Build a one-off gperf and put it in the PATH for the rest
of the target so the ONE call to gperf by the gcc build picks it up and
DTRT.

Reviewed by:	imp

Makefile.inc1

@@ -1535,7 +1535,22 @@ NXBMAKE=	${NXBENV} ${MAKE} \
 		MK_CLANG_EXTRAS=no MK_CLANG_FULL=no \
 		MK_LLDB=no
 
+# native-xtools is the current target for qemu-user cross builds of ports
+# via poudriere and the imgact_binmisc kernel module.
+# For non-clang enabled targets that are still using the in tree gcc
+# we must build a gperf binary for one instance of its Makefiles.  On
+# clang-enabled systems, the gperf binary is obsolete.
 native-xtools: .MAKE
+.if ${MK_GCC_BOOTSTRAP} != "no"
+	mkdir -p ${OBJTREE}/gperf_for_gcc/usr/bin
+	${_+_}@${ECHODIR} "===> ${_gperf} (obj,depend,all,install)"; \
+	cd ${.CURDIR}/${_gperf} && \
+	${NXBMAKE} DIRPRFX=${_gperf}/ obj && \
+	${NXBMAKE} DIRPRFX=${_gperf}/ depend && \
+	${NXBMAKE} DIRPRFX=${_gperf}/ all && \
+	${NXBMAKE} DIRPRFX=${_gperf}/ DESTDIR=${OBJTREE}/gperf_for_gcc install
+	PATH=${PATH}:${OBJTREE}/gperf_for_gcc/usr/bin
+.endif
 	mkdir -p ${OBJTREE}/nxb-bin/bin
 	mkdir -p ${OBJTREE}/nxb-bin/sbin
 	mkdir -p ${OBJTREE}/nxb-bin/usr