9996 use GCC 7 as default primary compiler

@@ -21,11 +21,11 @@
 # Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 # Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
 # Copyright 2012 Joshua M. Clulow <josh@sysmgr.org>
 # Copyright 2015, OmniTI Computer Consulting, Inc. All rights reserved.
 # Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
-# Copyright (c) 2019, Joyent, Inc.
+# Copyright 2019, Joyent, Inc.
 #
 # - This file is sourced by "bldenv.sh" and "nightly.sh" and should not
 #   be executed directly.
 # - This script is only interpreted by ksh93 and explicitly allows the
 #   use of ksh93 language extensions.

@@ -76,12 +76,15 @@
 # There can be several space-separated entries in SHADOW_* to run multiple
 # shadow compilers.
 #
 # To disable shadow compilation, unset SHADOW_* or set them to the empty string.
 #
-export SHADOW_CCS=gcc7,/usr/gcc/7/bin/gcc,gnu
-export SHADOW_CCCS=gcc7,/usr/gcc/7/bin/g++,gnu
+export GNUC_ROOT=/usr/gcc/7
+export PRIMARY_CCS=gcc7,$GNUC_ROOT/bin/gcc,gnu
+export PRIMARY_CCCS=gcc7,$GNUC_ROOT/bin/g++,gnu
+export SHADOW_CCS=gcc4,/opt/gcc/4.4.4/bin/gcc,gnu
+export SHADOW_CCCS=gcc4,/opt/gcc/4.4.4/bin/g++,gnu
 
 # uncomment to enable smatch
 #export ENABLE_SMATCH=1
 
 # Comment this out to disable support for SMB printing, i.e. if you