Travis test on osx, linux, gcc and clang

.travis.yml

@@ -1,7 +1,19 @@
 language: c
-before_install:
-   - sudo apt-get update -qq
-   - sudo apt-get install -qq texinfo
+sudo: false
+os:
+  - osx
+  - linux
+compiler:
+  - gcc
+  - clang
+addons:
+  apt:
+    packages:
+      - texinfo
 script:
+  - if [[ "${TRAVIS_OS_NAME}" == "osx" ]] && [[ "${CC}" == "gcc" ]]; then
+       export CC=gcc-4.8;
+       export CXX=g++-4.8;
+    fi
+  - $CC --version
   - ./configure && make && make check
-