Try using gcc rather than clang on travis

Author: maxbrunsfeld

.gitignore

@@ -4,4 +4,4 @@ build
 .clang_complete
 
 /browser.js
-emsdk_portable
+emsdk_portable

.travis.yml

@@ -10,6 +10,7 @@ node_js:
   - "node"
 
 before_install:
+  - export CXX="g++-4.8" CC="gcc-4.8"
   - curl https://cmake.org/files/v3.6/cmake-3.6.3-Linux-x86_64.tar.gz | tar xz
   - export PATH=${PWD}/cmake-3.6.3-Linux-x86_64/bin:$PATH
 
@@ -23,9 +24,6 @@ branches:
   only:
     - master
 
-env:
-  - CXX=clang++
-
 cache:
   directories:
     - emsdk_portable