native-xtools: Fix for GCC archs.

- This also adds in a _cleanobj step as needed.
- This redirects TARGET/TARGET_ARCH to NXB_TARGET/NXB_TARGET_ARCH in
  Makefile.inc1 as the main build needs to be for MACHINE rather
  than TARGET.

  First build the toolchain and then use that as an external toolchain
  to build the needed directories and NXB_TARGET-toolchain, all as
  MACHINE files though via TARGET_TRIPLE=MACHINE_TRIPLE.

  The NXBDIRS is evaluated in the 'everything' submake as it needs to be
  based on TARGET's src.opts.mk values, such as MK_GCC=yes when building
  on a MK_CLANG=yes MACHINE.  This can likely be changed to a specific
  _native-xtools-everything target later and the funky late evaluation
  of SUBDIR_OVERRIDE removed.

X-MFC-With:	r325001
Pointyhat to:	bdrewery
MFC after:	2 months
Sponsored by:	Dell EMC Isilon

Makefile

@@ -290,6 +290,15 @@ ${XTGTS}: _assert_target
 _TARGET?=	${MACHINE}
 _TARGET_ARCH?=	${MACHINE_ARCH}
 
+.if make(native-xtools*)
+NXB_TARGET:=		${_TARGET}
+NXB_TARGET_ARCH:=	${_TARGET_ARCH}
+_TARGET=		${MACHINE}
+_TARGET_ARCH=		${MACHINE_ARCH}
+_MAKE+=			NXB_TARGET=${NXB_TARGET} \
+			NXB_TARGET_ARCH=${NXB_TARGET_ARCH}
+.endif
+
 .if make(print-dir)
 .SILENT:
 .endif

Makefile.inc1

@@ -2110,7 +2110,7 @@ cross-tools: .MAKE .PHONY
 # to pickup.
 #
 NXBOBJROOT=	${OBJROOT}${MACHINE}.${MACHINE_ARCH}/nxb/
-NXBOBJTOP=	${NXBOBJROOT}${TARGET}.${TARGET_ARCH}
+NXBOBJTOP=	${NXBOBJROOT}${NXB_TARGET}.${NXB_TARGET_ARCH}
 NXTP?=		/nxb-bin
 .if ${NXTP:N/*}
 .error NXTP variable should be an absolute path
@@ -2180,20 +2180,27 @@ NXBDIRS+= \
     usr.bin/yacc \
     usr.sbin/chown
 
+SUBDIR_DEPEND_usr.bin/clang=	lib/clang
 .if ${MK_CLANG} != "no"
 NXBDIRS+=	lib/clang
-SUBDIR_DEPEND_usr.bin/clang=	lib/clang
 NXBDIRS+=	usr.bin/clang
-.elif ${MK_GCC} != "no"
+.endif
+.if ${MK_GCC} != "no"
 NXBDIRS+=	gnu/usr.bin/cc
 .endif
 .if ${MK_BINUTILS} != "no"
 NXBDIRS+=	gnu/usr.bin/binutils
 .endif
+# XXX: native-xtools passes along ${NXBDIRS} in SUBDIR_OVERRIDE that needs
+# to be evaluated after NXBDIRS is set.
+.if make(install) && !empty(SUBDIR_OVERRIDE)
+SUBDIR=	${SUBDIR_OVERRIDE}
+.endif
 
 NXBMAKEARGS+= \
 	OBJTOP=${NXBOBJTOP:Q} \
 	OBJROOT=${NXBOBJROOT:Q} \
+	MAKEOBJDIRPREFIX= \
 	-DNO_SHARED \
 	-DNO_CPU_CFLAGS \
 	-DNO_PIC \
@@ -2216,19 +2223,43 @@ NXBMAKEARGS+= \
 	MK_WARNS=no \
 	MK_ZFS=no
 
-
+.if make(native-xtools*) && \
+    (!defined(NXB_TARGET) || !defined(NXB_TARGET_ARCH))
+.error Missing NXB_TARGET / NXB_TARGET_ARCH
+.endif
 # For 'toolchain' we want to produce native binaries that themselves generate
 # native binaries.
 NXBTMAKE=	${NXBMAKEENV} ${MAKE} ${NXBMAKEARGS:N-DNO_PIC:N-DNO_SHARED} \
 		TARGET=${MACHINE} TARGET_ARCH=${MACHINE_ARCH}
 # For 'everything' we want to produce native binaries (hence -target to
 # be MACHINE) that themselves generate TARGET.TARGET_ARCH binaries.
 # TARGET/TARGET_ARCH are still passed along from user.
-NXBMAKE=	${NXBMAKEENV} ${MAKE} ${NXBMAKEARGS} \
+#
+# Use the toolchain we create as an external toolchain.
+.if ${USING_SYSTEM_COMPILER} == "yes" || ${XCC:N${CCACHE_BIN}:M/*}
+NXBMAKE+=	XCC="${XCC}" \
+		XCXX="${XCXX}" \
+		XCPP="${XCPP}"
+.else
+NXBMAKE+=	XCC="${NXBOBJTOP}/tmp/usr/bin/cc" \
+		XCXX="${NXBOBJTOP}/tmp/usr/bin/c++" \
+		XCPP="${NXBOBJTOP}/tmp/usr/bin/cpp"
+.endif
+NXBMAKE+=	${NXBMAKEENV} ${MAKE} -f Makefile.inc1 ${NXBMAKEARGS} \
+		TARGET=${NXB_TARGET} TARGET_ARCH=${NXB_TARGET_ARCH} \
 		TARGET_TRIPLE=${MACHINE_TRIPLE:Q}
+# NXBDIRS is improperly based on MACHINE rather than NXB_TARGET.  Need to
+# invoke a sub-make to reevaluate MK_GCC, etc, for NXBDIRS.
+NXBMAKE+=	SUBDIR_OVERRIDE='$${NXBDIRS:M*}'
+# Need to avoid the -isystem logic when using clang as an external toolchain
+# even if the TARGET being built for wants GCC.
+NXBMAKE+=	WANT_COMPILER_TYPE='$${X_COMPILER_TYPE}'
 native-xtools: .PHONY
+	${_+_}cd ${.CURDIR}; ${NXBTMAKE} _cleanobj
 	# Build the bootstrap/host/cross tools that produce native binaries
-	${_+_}cd ${.CURDIR}; ${NXBTMAKE} kernel-toolchain
+	# Pass along MK_GCC=yes to ensure GCC-needed build tools are built.
+	# We don't quite know what the NXB_TARGET wants so just build it.
+	${_+_}cd ${.CURDIR}; ${NXBTMAKE} kernel-toolchain MK_GCC=yes
 	# Populate includes/libraries sysroot that produce native binaries.
 	# This is split out from 'toolchain' above mostly so that target LLVM
 	# libraries have a proper LLVM_DEFAULT_TARGET_TRIPLE without
@@ -2238,10 +2269,9 @@ native-xtools: .PHONY
 	${_+_}cd ${.CURDIR}; ${NXBTMAKE} _includes MK_CLANG=no MK_GCC=no
 	${_+_}cd ${.CURDIR}; ${NXBTMAKE} _libraries MK_CLANG=no MK_GCC=no
 .if !defined(NO_OBJWALK)
-	${_+_}cd ${.CURDIR}; ${NXBMAKE} SUBDIR_OVERRIDE="${NXBDIRS:M*}" _obj
+	${_+_}cd ${.CURDIR}; ${NXBMAKE} _obj
 .endif
-	${_+_}cd ${.CURDIR}; ${NXBMAKE} SUBDIR_OVERRIDE="${NXBDIRS:M*}" \
-	    everything
+	${_+_}cd ${.CURDIR}; ${NXBMAKE} everything
 	@echo ">> native-xtools done.  Use 'make native-xtools-install' to install to a given DESTDIR"
 
 native-xtools-install: .PHONY
@@ -2250,9 +2280,8 @@ native-xtools-install: .PHONY
 	    -p ${NXBDESTDIR}/usr >/dev/null
 	mtree -deU -f ${.CURDIR}/etc/mtree/BSD.include.dist \
 	    -p ${NXBDESTDIR}/usr/include >/dev/null
-	${_+_}cd ${.CURDIR}; ${NXBMAKE} -f Makefile.inc1 \
+	${_+_}cd ${.CURDIR}; ${NXBMAKE} \
 	    DESTDIR=${NXBDESTDIR} \
-	    SUBDIR_OVERRIDE="${NXBDIRS:M*}" \
 	    -DNO_ROOT \
 	    install