travis: use Mac OS 10.14 and Xcode 10.2.1

The default Mac OS environment on travis no longer has brew bottle
support, so jobs time out.

Add the `osx_image` key to specify Mac OS 10.14 and Xcode 10.2.1.

Also try to re-enable link support using SFML.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

.travis.yml

@@ -66,12 +66,13 @@ matrix:
         - env: BUILD_ENV=mac
           language: cpp
           os: osx
+          osx_image: xcode10.2
           before_script:
               - ./installdeps
           script:
               - mkdir build
               - cd build
-              - cmake .. -DENABLE_SDL=ON -DENABLE_OPENAL=ON -DENABLE_LINK=OFF
+              - cmake .. -DENABLE_SDL=ON -DENABLE_OPENAL=ON -DENABLE_LINK=ON
               - make -j2
               - ./visualboyadvance-m.app/Contents/MacOS/visualboyadvance-m --help
           cache:

installdeps

@@ -1054,9 +1054,9 @@ brew_installdeps() {
     brews="nasm cmake ccache ffmpeg gettext libpng pkg-config sdl2 wxmac ccache"
 
     # sfml brew currently broken in the travis mac environment
-    if [ -z "$TRAVIS" ]; then
+#    if [ -z "$TRAVIS" ]; then
         brews="$brews sfml"
-    fi
+#    fi
 
     set --
     for f in $brews; do