trying build on OSX

.travis.yml

@@ -1,18 +1,27 @@
 language: cpp
-compiler:
-      - gcc
-#      - clang
-sudo: false
-dist: trusty
+matrix:
+  include:
+     - os: linux
+       dist: trusty
+       sudo: false
+       compiler: gcc
+     - os: osx
+       osx_image: xcode9.2
+       compiler: clang
 env:
       global:
            - secure: "pOICMBtfwljj450Vht1D2/XvtUm07edkbiUI0+PCnfuwiwBFJyqY919whZu+CrplQvkVS+RzvxT3wpgkVccflo0uvNJ7NwfKksRqrUKwTp59nGIwjUsnDjI3YkxOQyxIdIPsSm3bUxXVy/Jge0v6vzvbbPXKxyAxKsupnUBYOwM="
            - OMP_NUM_THREADS=4
            - VERBOSE=1
 before_script:
-        - mkdir -p build
+  - mkdir -p build
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then (git clone git://github.com/erikd/libsndfile.git && \
+	cd libsndfile && mkdir -p build && cd build && cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$HOME .. \
+	&& make && make install)
 script:
-  - "[ ${COVERITY_SCAN_BRANCH} == 1 ] || (cd $TRAVIS_BUILD_DIR/build && cmake .. -DBUILD_STATIC_LIBRARY=ON -DBUILD_TESTS=ON && make && make test && make regression && make csdtests)"
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; "[ ${COVERITY_SCAN_BRANCH} == 1 ] || (cd $TRAVIS_BUILD_DIR/build && cmake .. -DBUILD_STATIC_LIBRARY=ON -DBUILD_TESTS=ON && make && make test && make regression && make csdtests)"
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; "(cd $TRAVIS_BUILD_DIR/build && cmake .. -DBUILD_STATIC_LIBRARY=ON -DBUILD_TESTS=ON && make)"
+
 ###
 
 addons: