ansible,jenkins: install gcc-7 on ubuntu1604 machines, use on node>12

Ref: #1970

ansible/roles/baselayout/tasks/main.yml

@@ -118,6 +118,15 @@
     - gcc
     - g++
 
+- name: ubuntu1604 | update package alternatives
+  when: os == "ubuntu1604"
+  alternatives: link=/usr/bin/{{ gcc }} name={{ gcc }} path=/usr/bin/{{ gcc }}-5
+  loop_control:
+    loop_var: gcc
+  with_items:
+    - gcc
+    - g++
+
 - name: smartos17 | update gcc symlinks
   when: os == "smartos17"
   file:

ansible/roles/baselayout/tasks/partials/repo/ubuntu1604.yml

@@ -0,0 +1,12 @@
+---
+
+#
+# add PPA for gcc updates
+#
+
+- name: "repo : add Ubuntu Toolchain PPA"
+  apt_repository:
+    repo: 'ppa:ubuntu-toolchain-r/test'
+    state: present
+    update_cache: yes
+  register: has_updated_package_repo

ansible/roles/baselayout/vars/main.yml

@@ -120,7 +120,7 @@ packages: {
   ],
 
   ubuntu: [
-    'ccache,g++,gcc,git,libfontconfig1,sudo',
+    'ccache,g++,gcc,g++-6,gcc-6,git,libfontconfig1,sudo',
   ],
 
   ubuntu1404: [

jenkins/scripts/select-compiler.sh

@@ -14,6 +14,8 @@ if [ "$DONTSELECT_COMPILER" != "DONT" ]; then
     *ppc64*le* ) SELECT_ARCH=PPC64LE ;;
     *s390x* ) SELECT_ARCH=S390X ;;
     *aix* ) SELECT_ARCH=AIXPPC ;;
+    *x64* ) SELECT_ARCH=X64 ;;
+    *arm64* ) SELECT_ARCH=ARM64 ;;
   esac
 fi
 
@@ -112,4 +114,33 @@ elif [ "$SELECT_ARCH" = "AIXPPC" ]; then
     # front of PATH
     echo "Compiler set to default at 4.8.5"
   fi
+
+elif [ "$SELECT_ARCH" = "X64" ]; then
+  echo "Setting compiler for Node version $NODEJS_MAJOR_VERSION on x64"
+
+
+  if test $nodes = "centos6-64-gcc48"; then
+    . /opt/rh/devtoolset-2/enable
+    echo "Compiler set to devtoolset-2"
+  elif [[ "$nodes" =~ centos[67]-64-gcc6 ]]; then
+    . /opt/rh/devtoolset-6/enable
+    echo "Compiler set to devtoolset-6"
+  elif test $nodes = "ubuntu1604"; then
+    if [ "$NODEJS_MAJOR_VERSION" -gt "12" ]; then
+      export CC="gcc-6"
+      export CXX="g++-6"
+      export LINK="g++-6"
+      echo "Compiler set to GCC 6 for $NODEJS_MAJOR_VERSION"
+    fi
+  fi
+
+elif [ "$SELECT_ARCH" = "ARM64" ]; then
+  echo "Setting compiler for Node version $NODEJS_MAJOR_VERSION on arm64"
+
+
+  if [[ "$nodes" =~ centos[67]-arm64-gcc6 ]]; then
+    . /opt/rh/devtoolset-6/enable
+    echo "Compiler set to devtoolset-6"
+  fi
+
 fi