Add GitHub Workflow

.github/workflows/build.yml

@@ -0,0 +1,24 @@
+name: Build JDK for ARM
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-18.04
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+
+    - name: Build with CI build script
+      run: ./ci_build.sh
+
+    - name: Upload build output
+      uses: actions/upload-artifact@v1
+      with:
+        name: jre
+        path: jre.tar.xz

buildjdk.sh

@@ -5,7 +5,11 @@ export FREETYPE_DIR=`pwd`/freetype-2.6.2/build_android-arm
 export CUPS_DIR=`pwd`/cups-2.2.4
 
 # My system's JDK is too old (7.0), so we add an Oracle boot JDK.
-export PATH=`pwd`/jdk1.8.0_162/bin:$PATH
+# Set "USE_SYSTEM_JDK_8=1" to use system jdk instead
+if [ -z "$USE_SYSTEM_JDK_8" ]
+then
+	export PATH=`pwd`/jdk1.8.0_162/bin:$PATH
+fi
 
 cd openjdk
 rm -rf build

ci_build.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -e
+# We have OpenJDK 8, good enough
+export USE_SYSTEM_JDK_8=1
+wget -nv -O android-ndk-r10e-linux-x86_64.zip "https://dl.google.com/android/repository/android-ndk-r10e-linux-x86_64.zip"
+./extractndk.sh
+./getlibs.sh
+./maketoolchain.sh
+./clonejdk.sh
+./buildlibs.sh
+./buildjdk.sh
+./removejdkdebuginfo.sh
+./tarjdk.sh