www/newsboat: add MODCARGO_ENV to MAKE_ENV

Hi,

I am working to update lang/rust to 1.36.0. It requires a writable CARGO_HOME directory.

The following diff explicitly adds MODCARGO_ENV to MAKE_ENV, in order to
pass all configuration stuff from devel/cargo module to www/newsboat.

newsboat is special as it uses devel/cargo module to maintain
MODCARGO_CRATES, but doesn't use it to build. it is why the environment
isn't passed automatically.

Please note that it will also make the build of newsboat respect
MAKE_JOBS.

Comments or OK ?
--
Sebastien Marie

Index: Makefile
===================================================================
RCS file: /cvs/ports/www/newsboat/Makefile,v
retrieving revision 1.10
diff -u -p -r1.10 Makefile
--- Makefile 20 May 2019 22:15:27 -0000 1.10
+++ Makefile 1 Jul 2019 07:19:32 -0000
@@ -116,7 +116,9 @@ LIB_DEPENDS = databases/sqlite3 \
textproc/libxml \
net/curl

-MAKE_ENV = CXX="${CXX}" CXXFLAGS="${CXXFLAGS}"
+MAKE_ENV = ${MODCARGO_ENV} \
+ CXX="${CXX}" \
+ CXXFLAGS="${CXXFLAGS}"
FAKE_FLAGS = mandir="${PREFIX}/man"

USE_GMAKE = Yes