try to build c++11 on travis

.travis.yml

@@ -2,6 +2,8 @@
 language: cpp
 compiler: gcc
 sudo: false
+install:
+- if [ "$CXX" = "g++" ]; then export CXX="g++-4.8" CC="gcc-4.8"; fi
 script: ./autogen.sh && ./configure && make distcheck -j3
 after_script: test -e test/test-suite.log  && cat test/test-suite.log
 
@@ -16,6 +18,8 @@ addons:
     packages:
     - libgpm-dev
     - re2c
+    - gcc-4.8
+    - g++-4.8
   coverity_scan:
     project:
       name: "tstack/lnav"