Add automated build for PSP

.github/workflows/psp.yaml

@@ -0,0 +1,18 @@
+name: Build (Sony Playstation Portable)
+
+on: [push, pull_request]
+
+jobs:
+  psp:
+    runs-on: ubuntu-latest
+    container: pspdev/pspdev:latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup dependencies
+      run: |
+        apk update 
+        apk add cmake gmp mpc1 mpfr4 make
+    - name: Configure CMake
+      run: cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=$PSPDEV/psp/share/pspdev.cmake
+    - name: Build
+      run: cmake --build build