www/node: set environment variables for host build

The Node.js build system supports cross-compilation via node-gyp, which
picks up CC, CXX, LINK, C*FLAGS, and LDFLAGS from the environment for the
target build, but not for the host. We need to set the environment variables
for the "host" build.

This unbreaks the build on powerpc64.

PR:		233650
Reported by:	Piotr Kubaj <pkubaj@anongoth.pl>
Sponsored by:	Miles AS
Differential Revision:	https://reviews.freebsd.org/D19250

www/node/Makefile

@@ -12,7 +12,6 @@ COMMENT=	V8 JavaScript for client and server
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
-BROKEN_powerpc64=	fails to build: KeyError: 'action'
 BROKEN_SSL=		openssl libressl libressl-devel
 BROKEN_SSL_REASON=	Node.js 11.x requires OpenSSL 1.1.x or the BUNDLED_SSL option enabled
 ONLY_FOR_ARCHS=		aarch64 amd64 armv6 armv7 i386 powerpc64
@@ -31,6 +30,7 @@ OPTIONS_EXCLUDE_aarch64=	DTRACE
 # dt_modtext:/usr/src/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c(820): arm not implemented
 OPTIONS_EXCLUDE_armv6=		DTRACE
 OPTIONS_EXCLUDE_armv7=		DTRACE
+OPTIONS_EXCLUDE_powerpc64=	DTRACE
 
 BUNDLED_SSL_DESC=		Use node.js's bundled OpenSSL implementation
 BUNDLED_SSL_USES_OFF=		ssl
@@ -60,7 +60,9 @@ SHEBANG_FILES=	tools/specialize_node_d.py tools/genv8constants.py
 
 PREFIX_RELDEST=	${PREFIX:S,^${DESTDIR},,}
 REINPLACE_ARGS=	-i ''
-MAKE_ENV+=	CC.host=${CC} CXX.host=${CXX} LINK.host=${CXX} LINK.target=${CXX}
+MAKE_ENV+=	CC.host=${CC} CFLAGS.host="${CFLAGS}" \
+		CXX.host=${CXX} CXXFLAGS.host="${CXXFLAGS}" \
+		LINK.host=${CXX} LDFLAGS.host="${LDFLAGS}"
 
 LIB_DEPENDS+=	libcares.so:dns/c-ares\
 		libuv.so:devel/libuv \