ci: added Github Actions build workflow

.github/workflows/build.yml

@@ -0,0 +1,55 @@
+name: build
+
+on: [push]
+
+jobs:
+  linux_clang6:
+    name: "Linux Clang6"
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: 'recursive'
+    - run: ./.travis/linux/run-container.sh 6
+    - uses: actions/upload-artifact@v2
+      with: 
+        path: upload/*
+
+  linux_clang8:
+    name: "Linux Clang8"
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: 'recursive'
+    - run: ./.travis/linux/run-container.sh 8
+    - uses: actions/upload-artifact@v2
+      with: 
+        path: upload/*
+
+  android:
+    name: "Android"
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: 'recursive'
+    - run: ./.travis/android/run-container.sh
+    - uses: actions/upload-artifact@v2
+      with: 
+        path: upload/*
+
+  macos:
+    name: "macOS"
+    runs-on: macOS-10.15
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: 'recursive'
+    - run: ./.travis/macos/install-dependencies.sh
+    - run: ./.travis/macos/build.sh
+    - uses: actions/upload-artifact@v2
+      with: 
+        path: upload/*
+
+# TODO: Add Windows

.travis/android/build.sh

@@ -3,10 +3,7 @@
 
 cd /home/build
 
-export BUILD_MODE=release
-if [ "$TRAVIS_PULL_REQUEST" = "true" ]; then
-    export BUILD_MODE=debug
-fi
+export BUILD_MODE=${BUILD_MODE:-debug}
 
 export OS=android
 export DATE=$(date +%Y%m%d)

.travis/android/run-container.sh

@@ -2,17 +2,23 @@
 # Run in Travis to launch container
 
 # Setup signing
+export BUILD_MODE="debug"
 if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then 
     openssl aes-256-cbc -K $encrypted_7333c7dd5b15_key -iv $encrypted_7333c7dd5b15_iv -in android/avocado.keystore.enc -out android/avocado.keystore -d
+    export BUILD_MODE="release"
+fi
+
+if [ "$GITHUB_ACTIONS" = "true" ]; then
+    export BUILD_MODE="debug"
 fi
 
 mkdir -p "$HOME/.ccache"
 
 docker run \
     -e CI=$CI \
-    -e TRAVIS_PULL_REQUEST=$TRAVIS_PULL_REQUEST \
+    -e BUILD_MODE=$BUILD_MODE \
+    -e keystore_password="$keystore_password" \
     -v $(pwd):/home/build \
     -v "$HOME/.ccache":/root/.ccache \
-    -e keystore_password="$keystore_password" \
     avocadoemu/android \
     /bin/bash -ex /home/build/.travis/android/build.sh

.travis/macos/install-dependencies.sh

@@ -9,5 +9,5 @@ mv premake5 /usr/local/bin/
 rm premake-$PREMAKE_VERSION-macosx.tar.gz
 
 # Download SDL2 and ccache
-brew update
-brew install sdl2 ccache
+brew update > /dev/null
+brew install sdl2 ccache