Trying alternate approach for sharing env vars from the matrix with the

install.

.travis.yml

@@ -12,10 +12,7 @@ matrix:
           packages:
             - g++-6
       env:
-         - MATRIX_EVAL="CC=gcc-6 && CXX=g++-6"
-before_install:
-  - eval "${MATRIX_EVAL}"
-
+         - CC=gcc-6 CXX=g++-6
 install:
   - pip install -r requirements.txt
   - python setup.py build install