Revert "Disable OSX builds"

Author: peterschrammel

.travis.yml

@@ -39,6 +39,32 @@ jobs:
       # env: COMPILER=g++-5 SAN_FLAGS="-fsanitize=undefined -fno-sanitize-recover -fno-omit-frame-pointer"
       env: COMPILER="ccache g++-5"
 
+    # OS X using g++
+    - stage: Test different OS/CXX/Flags
+      os: osx
+      sudo: false
+      compiler: gcc
+      cache: ccache
+      before_install:
+          #we create symlink to non-ccache gcc, to be used in tests
+        - mkdir bin ; ln -s /usr/bin/gcc bin/gcc
+        - HOMEBREW_NO_AUTO_UPDATE=1 brew install ccache
+        - export PATH=/usr/local/opt/ccache/libexec:$PATH
+      env: COMPILER="ccache g++"
+
+    # OS X using clang++
+    - stage: Test different OS/CXX/Flags
+      os: osx
+      sudo: false
+      compiler: clang
+      cache: ccache
+      before_install:
+        - HOMEBREW_NO_AUTO_UPDATE=1 brew install ccache
+        - export PATH=/usr/local/opt/ccache/libexec:$PATH
+      env:
+        - COMPILER="ccache clang++ -Qunused-arguments -fcolor-diagnostics"
+        - CCACHE_CPP2=yes
+
     # Ubuntu Linux with glibc using g++-5, debug mode
     - stage: Test different OS/CXX/Flags
       os: linux
@@ -127,6 +153,18 @@ jobs:
         - cmake --build build -- -j4
       script: (cd build; ctest -V -L CORE)
 
+    - stage: Test different OS/CXX/Flags
+      os: osx
+      cache: ccache
+      env:
+        - BUILD_SYSTEM=cmake
+        - CCACHE_CPP2=yes
+      install:
+        - cmake -H. -Bbuild '-DCMAKE_BUILD_TYPE=Release' '-DCMAKE_OSX_ARCHITECTURES=x86_64'
+        - cmake --build build -- -j4
+      script: (cd build; ctest -V -L CORE)
+
+
   allow_failures:
     - <<: *linter-stage