Add SDL3 as a platform backend

- Select backend using `-Dplatform_backend=X` where X is 'sdl' or 'sokol'
- Default backend is sokol
- Adds SDL build to 3rdparty
    - SDL is only built when selected
- Add GitHub actions to ensure the build works for supported targets
- Renamed AppBackendConfig => PlatformHooks
- Linux and Emscripten Ahoy! (Windows and MacOS pending)
- sokol_gfx swapchain parameters initialized differently for SDL

Author: photex

.github/workflows/ci.yml

@@ -0,0 +1,57 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest]
+        backend: [sdl, sokol]
+        optimize: [Debug]
+    name: Zig Build
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: mlugg/setup-zig@v1
+      with:
+        version: 0.13.0
+
+    - if: ${{ matrix.os == 'ubuntu-latest' }}
+      run: |
+        sudo apt update
+        sudo apt install \
+          build-essential \
+          libasound2-dev \
+          libpulse-dev \
+          libaudio-dev \
+          libjack-dev \
+          libsndio-dev \
+          libx11-dev \
+          libxext-dev \
+          libxrandr-dev \
+          libxcursor-dev \
+          libxfixes-dev \
+          libxi-dev \
+          libxss-dev \
+          libxkbcommon-dev \
+          libdrm-dev \
+          libgbm-dev \
+          libgl1-mesa-dev \
+          libgles2-mesa-dev \
+          libegl1-mesa-dev \
+          libdbus-1-dev \
+          libibus-1.0-dev \
+          libudev-dev \
+          fcitx-libs-dev
+
+    - name: Build Linux
+      run: zig build -Dplatform_backend=${{ matrix.backend }} -Doptimize=${{ matrix.optimize }}
+
+    - name: Build Windows
+      run: zig build -Dplatform_backend=${{ matrix.backend }} -Doptimize=${{ matrix.optimize }} -Dtarget=x86_64-windows
+
+    - name: Build Wasm32
+      run: zig build -Dplatform_backend=${{ matrix.backend }} -Doptimize=${{ matrix.optimize }} -Dtarget=wasm32-emscripten
+

.gitignore

@@ -2,3 +2,4 @@ zig-cache
 .zig-cache
 zig-out
 .DS_Store
+*.sublime-workspace