ci: Add GitHub action

.github/workflows/build.yml

@@ -0,0 +1,25 @@
+name: Build
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Install devkitPro
+      run: |
+        sudo dpkg --add-architecture i386
+        curl -L https://apt.devkitpro.org/devkitpro-pub.gpg | sudo apt-key add -
+        sudo add-apt-repository "deb https://apt.devkitpro.org stable main"
+        sudo apt-get -y install devkitpro-pacman wine32
+        sudo dkp-pacman -S --noconfirm gamecube-dev
+    - uses: actions/checkout@v3
+    - name: Download compilers
+      run: |
+        curl -L https://cdn.discordapp.com/attachments/727918646525165659/917185027656286218/GC_WII_COMPILERS.zip \
+          | bsdtar -xvf- -C tools --exclude Wii
+        mv tools/GC tools/mwcc_compiler
+    - name: make
+      run: make -j