Fix macOS CMake CI builds

Author: zbeekman

.travis.yml

@@ -25,6 +25,7 @@ matrix:
           GCC=9
           CC=gcc-9
           CXX=g++-9
+          FC=gfortran-9
       addons:
         homebrew:
           packages:
@@ -51,6 +52,7 @@ matrix:
         - GCC=9
           FC=gcc-${GCC}
           CC=gcc-${GCC}
+          CXX=gcc-${GCC}
       addons:
         homebrew:
           brewfile: true

developer-scripts/travis/install.osx.sh

@@ -36,12 +36,12 @@ brew outdated
 type -a cmake || echo "CMake not installed"
 cmake --version || true
 
-echo "CC: ${CC}"
+echo "CC: ${CC:-none defined}"
 echo "\$CC --version:"
-$CC --version || true
+${CC:-} --version || true
 
-echo "FC: ${FC}"
+echo "FC: ${FC:-none-defined}"
 echo "\$FC --version:"
-$FC --version || true
+${FC:-} --version || true
 
 echo "Done."