Update .travis.yml

.travis.yml

@@ -40,6 +40,10 @@ matrix:
     compiler: clang
     env:
     - MATRIX_EVAL="export CONFIG=Debug && PYTHON=python3"
+  - os: osx
+    compiler: clang
+    env:
+    - MATRIX_EVAL="export CONFIG=Debug && PYTHON=python3 CMAKE_EXTRA='-DLIBIGL_EIGEN_VERSION=3.3.7 -DLIBIGL_EIGEN_MD5=f2a417d083fe8ca4b8ed2bc613d20f07'""
 
 install:
 - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then export PATH="/usr/local/opt/ccache/libexec:$PATH"; fi