experimentally add osx in travis.yml

.travis.yml

@@ -1,31 +1,41 @@
 dist: trusty
-language: cpp
 
 matrix:
   include:
-    - compiler: gcc
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-5"
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         packages:
-            - build-essential
         - g++-5
-      env: COMPILER=g++-5
+        - build-essential
-    - compiler: clang
+        - cmake
+        - libboost-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-3.7"
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-precise-3.7
         packages:
-            - build-essential
         - clang-3.7
-      env: COMPILER=clang++-3.7
+        - build-essential
+        - cmake
+        - libboost-dev
+  - os: osx
+    language: cpp
+    compiler: clang
 
-install:
+before_install:
-- sudo apt-get -qq update;
+    - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; fi
-- sudo apt-get -qq install libboost-all-dev;
+    - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install cmake boost; fi
 
 script:
 - mkdir build
@@ -34,4 +44,3 @@ script:
 - cmake -DCMAKE_CXX_COMPILER=$COMPILER ..
 - make
 - make test
-