Another try at Travis...

Author: earlephilhower

.travis.yml

@@ -6,56 +6,16 @@ git:
   depth: 1
   submodules: false
 
-# From https://docs.travis-ci.com/user/languages/cpp/ - to get less ancient GCC/G++
-matrix:
-  include:
-    # works on Precise and Trusty
-    - os: linux
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-4.9
-      env:
-         - MATRIX_EVAL="CC=gcc-4.9 && CXX=g++-4.9"
-
-    # works on Precise and Trusty
-    - os: linux
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-5
-      env:
-         - MATRIX_EVAL="CC=gcc-5 && CXX=g++-5"
-
-    # works on Precise and Trusty
-    - os: linux
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-6
-      env:
-        - MATRIX_EVAL="CC=gcc-6 && CXX=g++-6"
-
-    # works on Precise and Trusty
-    - os: linux
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-7
-      env:
-        - MATRIX_EVAL="CC=gcc-7 && CXX=g++-7"
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - g++-7
+      - gcc-7
 
 before_install:
   - git submodule update --init  # no recursive update
-  - eval "${MATRIX_EVAL}"
 
 cache:
   directories:
@@ -128,6 +88,7 @@ jobs:
       stage: build
       script: $TRAVIS_BUILD_DIR/tests/ci/host_test.sh
       install: sudo apt-get install valgrind lcov
+      env: CC=gcc-7 CXX=g++-7
 
     - name: "Docs"
       stage: build
@@ -144,6 +105,7 @@ jobs:
     - name: "Mock trivial test"
       stage: build
       script: $TRAVIS_BUILD_DIR/tests/buildm.sh
+      env: CC=gcc-7 CXX=g++-7
 
     - name: "Boards"
       stage: build