attempt some CI building using github actions

.github/workflows/ci-libretro-default.yml

@@ -0,0 +1,11 @@
+name: CI (libretro default)
+on: [push, pull_request]
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+    - name: make
+      run: LDFLAGS=-Wl,--no-undefined make -f Makefile.libretro

.github/workflows/ci-linux.yml

@@ -0,0 +1,17 @@
+name: CI (Linux)
+on: [push, pull_request]
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+    - name: Install dependencies
+      run: |
+        sudo apt-get update -qq
+        sudo apt-get install -y libsdl1.2-dev libasound2-dev libpng-dev libz-dev
+    - name: configure
+      run: DUMP_CONFIG_LOG=1 ./configure
+    - name: make
+      run: make

.github/workflows/ci-pandora.yml

@@ -0,0 +1,20 @@
+name: CI (pandora)
+on: [push, pull_request]
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+    - name: Install dependencies
+      run: |
+        whoami
+        sudo apt-get update -qq
+        sudo apt-get install -y wget
+        wget http://notaz.gp2x.de/misc/pnd/toolchains/arm-gcc-4.9.4_with_libs_small.tar.xz
+        tar -C /tmp/ -xf arm-gcc-4.9.4_with_libs_small.tar.xz
+    - name: configure
+      run: DUMP_CONFIG_LOG=1 PATH=$PATH:/tmp/arm-gcc-4.9.4/bin CPATH=/tmp/arm-gcc-4.9.4/arm-unknown-linux-gnueabi/sysroot/usr/local/include/ CROSS_COMPILE=arm-unknown-linux-gnueabi- ./configure --platform=pandora
+    - name: make
+      run: PATH=$PATH:/tmp/arm-gcc-4.9.4/bin CPATH=/tmp/arm-gcc-4.9.4/arm-unknown-linux-gnueabi/sysroot/usr/local/include/ CROSS_COMPILE=arm-unknown-linux-gnueabi- make