[macOS] Parametrize Qt5 version used on CI

.travis.yml

@@ -15,6 +15,7 @@ env:
    # The next declaration is the encrypted COVERITY_SCAN_TOKEN, created
    #   via the "travis encrypt" command using the project repo's public key
    - secure: "jybGzAdUbqt9vWR/GEnRd96BgAi/7Zd1+2HK68j/i/8+/1YH2XxLOy4Jv/DUBhBlJIkxs/Xv8dRcUlFOclZDHX1d/9Qnsqd3oUVkD7k1y7cTOWy9TBQaE/v/kZo3LpzA3xPwwthrb0BvqIbOfIELi5fS5s8ba85WFRg3AX70wWE="
+   - macos_qt_formula=qt@5.5
 addons:
   apt:
     sources:

CI/before_install.osx.sh

@@ -5,7 +5,7 @@ brew update
 brew rm cmake || true
 brew rm pkgconfig || true
 brew rm qt5 || true
-brew install cmake pkgconfig qt55
+brew install cmake pkgconfig $macos_qt_formula
 
 curl http://downloads.openmw.org/osx/dependencies/openmw-deps-263d4a8.zip -o ~/openmw-deps.zip
 unzip ~/openmw-deps.zip -d /private/tmp/openmw-deps > /dev/null

CI/before_script.osx.sh

@@ -4,7 +4,7 @@ export CXX=clang++
 export CC=clang
 
 DEPENDENCIES_ROOT="/private/tmp/openmw-deps/openmw-deps"
-QT_PATH=`brew --prefix qt@5.5`
+QT_PATH=`brew --prefix $macos_qt_formula`
 
 mkdir build
 cd build