suricata, librsvg : set CARGO_HOME for upcoming lang/rust-1.36

Hi,

I am working on updating lang/rust to 1.36.0

The release ships a new version of cargo which will want to write a file
in $HOME (a lock file to manage concurrent access on package cache).

To avoid an error while acquiring package cache lock, CARGO_HOME should
be defined to a directory writable by the build. The default value of
CARGO_HOME is "$HOME/.cargo", so alternatively PORTHOME in the port
could be set too.

As i think it is less invasive to set CARGO_HOME, I followed this way.

The following diff takes care of:
- security/suricata : configure look for CARGO_HOME env var
- x11/gnome/librsvg : set CARGO_HOME via MAKE_ENV

Some others ports not using devel/cargo sets PORTHOME (hey firefox o/)
so the problem doesn't occurs. And ports using devel/cargo modules
already defines CARGO_HOME by default.

One possible leftover is devel/meson where lang/rust is a TEST_DEPS. But
it seems it is directly using rustc compiler and not cargo. So I assume
it is fine.

No package bump as it is a build setting that don't affect anything with
rust-1.35 we have in port.

Comments or OK ?
--
Sebastien Marie

Index: security/suricata/Makefile
===================================================================
RCS file: /cvs/ports/security/suricata/Makefile,v
retrieving revision 1.20
diff -u -p -r1.20 Makefile
--- security/suricata/Makefile 3 May 2019 06:22:34 -0000 1.20
+++ security/suricata/Makefile 30 Jun 2019 10:05:52 -0000
@@ -49,7 +49,8 @@ CONFIGURE_STYLE = autoconf
AUTOCONF_VERSION = 2.69

CONFIGURE_ENV = ac_cv_path_HAVE_PDFLATEX= \
- ac_cv_path_HAVE_GIT_CMD=
+ ac_cv_path_HAVE_GIT_CMD= \
+ CARGO_HOME=${WRKBUILD}/cargo-home

CONFIGURE_ARGS = --disable-gccmarch-native \
--enable-ipfw
Index: x11/gnome/librsvg/Makefile
===================================================================
RCS file: /cvs/ports/x11/gnome/librsvg/Makefile,v
retrieving revision 1.148
diff -u -p -r1.148 Makefile
--- x11/gnome/librsvg/Makefile 13 May 2019 22:47:45 -0000 1.148
+++ x11/gnome/librsvg/Makefile 30 Jun 2019 07:25:33 -0000
@@ -19,7 +19,8 @@ SHARED_LIBS += rsvg-2 39.
GNOME_VERSION= ${STABLE_VERSION}
BUILD_DEPENDS= lang/rust
PKG_ARGS= -Dold=0 -Dstable=1
-MAKE_ENV+= CARGO_BUILD_JOBS=${MAKE_JOBS}
+MAKE_ENV+= CARGO_BUILD_JOBS=${MAKE_JOBS} \
+ CARGO_HOME=${WRKBUILD}/cargo-home
.else
### old
REVISION= 3