travis: Compile on macOS 10.13 with more up to date compiler

.travis.yml

@@ -32,7 +32,7 @@ matrix:
     - os: osx
       env: NAME="macos build"
       sudo: false
-      osx_image: xcode10.2
+      osx_image: xcode10
       install: "./.travis/macos/deps.sh"
       script: "./.travis/macos/build.sh"
       after_success: "./.travis/macos/upload.sh"

.travis/macos/build.sh

@@ -4,7 +4,12 @@ set -o pipefail
 
 export MACOSX_DEPLOYMENT_TARGET=10.13
 export Qt5_DIR=$(brew --prefix)/opt/qt5
-export PATH="/usr/local/opt/ccache/libexec:$PATH"
+export PATH="/usr/local/opt/ccache/libexec:/usr/local/opt/llvm/bin:$PATH"
+
+export CC="clang"
+export CXX="clang++"
+export LDFLAGS="-L/usr/local/opt/llvm/lib"
+export CPPFLAGS="-I/usr/local/opt/llvm/include"
 
 mkdir build && cd build
 cmake .. -DCMAKE_BUILD_TYPE=Release -DENABLE_QT_TRANSLATION=ON -DCITRA_ENABLE_COMPATIBILITY_REPORTING=${ENABLE_COMPATIBILITY_REPORTING:-"OFF"} -DENABLE_COMPATIBILITY_LIST_DOWNLOAD=ON -DUSE_DISCORD_PRESENCE=ON -DENABLE_FFMPEG_AUDIO_DECODER=ON -DENABLE_FFMPEG_VIDEO_DUMPER=ON

.travis/macos/deps.sh

@@ -2,5 +2,5 @@
 
 brew update
 brew unlink python@2
-brew install qt5 sdl2 p7zip ccache ffmpeg
+brew install qt5 sdl2 p7zip ccache ffmpeg llvm
 pip3 install macpack