Using compiler environment for travis

.travis.yml

@@ -1,16 +1,31 @@
 language: node_js
+
 node_js:
-- 6
-- 8
+  - 6
+  - 8
+
 matrix:
   fast_finish: true
-cache:
-  directories:
-    - $HOME/.npm
+
+env:
+- CXX=g++-4.8
+
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - g++-4.8
+
+before_install:
+  - npm install -g npm@latest
+  - npm --version
+
 notifications:
   email: false
   slack:
     secure: 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
-before_install:
-  - npm install -g npm@latest
-  - npm --version
+
+cache:
+  directories:
+    - $HOME/.npm