Merge pull request #1977 from xoviat/travis

[travis] update gcc

.travis.yml

@@ -4,10 +4,14 @@ sudo: false
 
 addons:
   apt:
+    sources:
+      - ubuntu-toolchain-r-test
     packages:
       - gdb
       - python-dbg
       - python3-dbg
+      - gcc-6
+      - g++-6
 
 cache:
   pip: true
@@ -33,7 +37,7 @@ env:
     - CCACHE_SLOPPINESS=pch_defines,time_macros
     - CCACHE_COMPRESS=1
     - CCACHE_MAXSIZE=100M
-    - PATH="/usr/lib/ccache:$PATH"
+    - PATH="/usr/lib/ccache:$HOME/gcc-symlinks:$PATH"
   matrix:
     - BACKEND=c
     - BACKEND=cpp
@@ -84,6 +88,15 @@ branches:
     - release
 
 before_install:
+  - |
+    if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+      mkdir "$HOME/gcc-symlinks"
+      ln -s /usr/bin/gcc-6 $HOME/gcc-symlinks/gcc 
+      ln -s /usr/bin/g++-6 $HOME/gcc-symlinks/g++ 
+      
+      gcc --version
+    fi
+
   - |
     if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then # Install Miniconda
       curl -s -o miniconda.sh https://repo.continuum.io/miniconda/Miniconda$PY-latest-MacOSX-x86_64.sh;