Tentative fix of travis

.travis.yml

@@ -487,7 +487,7 @@ matrix:
     - os: linux
       dist: bionic
       env:
-        - MATRIX_EVAL="CC=clang-7.0 && CXX=clang++-7.0 && INFO=C++17-pure-release"
+        - MATRIX_EVAL="CC=clang-7.0 && INFO=C++17-pure-release"
       script:
         - cmake --version
         - mkdir ./build_pure_17_release
@@ -499,7 +499,7 @@ matrix:
     - os: linux
       dist: bionic
       env:
-        - MATRIX_EVAL="CC=clang-5.0 && CXX=clang++-7.0 && INFO=C++17-pure-debug"
+        - MATRIX_EVAL="CC=clang-7.0 && INFO=C++17-pure-debug"
       script:
         - cmake --version
         - mkdir ./build_pure_17_debug
@@ -511,7 +511,7 @@ matrix:
     - os: linux
       dist: bionic
       env:
-        - MATRIX_EVAL="CC=clang-7.0 && CXX=clang++-7.0 && INFO=C++17-sse3-release"
+        - MATRIX_EVAL="CC=clang-7.0 && INFO=C++17-sse3-release"
       script:
         - cmake --version
         - mkdir ./build_sse3_17_release
@@ -523,7 +523,7 @@ matrix:
     - os: linux
       dist: bionic
       env:
-        - MATRIX_EVAL="CC=clang-7.0 && CXX=clang++-7.0 && INFO=C++17-sse3-debug"
+        - MATRIX_EVAL="CC=clang-7.0 && INFO=C++17-sse3-debug"
       script:
         - cmake --version
         - mkdir ./build_sse3_17_debug
@@ -535,7 +535,7 @@ matrix:
     - os: linux
       dist: bionic
       env:
-        - MATRIX_EVAL="CC=clang-7.0 && CXX=clang++-7.0 && INFO=C++17-ssse3-release"
+        - MATRIX_EVAL="CC=clang-7.0 && && INFO=C++17-ssse3-release"
       script:
         - cmake --version
         - mkdir ./build_ssse3_17_release