Add build scripts

Jenkinsfile

@@ -0,0 +1,21 @@
+pipeline {
+    agent  { label 'ubuntu' }
+    environment {
+        PATH = "/home/jenkins/depot_tools:${env.PATH}"
+    }
+
+    stages {
+        stage('Build release') {
+            steps {
+                script {
+                    sh '''#!/bin/sh
+                    set -xe
+                    . dev/tools/envsetup.sh
+                    gclient sync -D
+                    ./dev/tools/build_release.sh
+                    '''
+                }
+            }
+        }
+    }
+}

dev/tools/build_release.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+cd engine/src/out/
+
+et build -c ci/android_release -j $(nproc)
+et build -c host_release -j $(nproc)
+
+rm android_release || true
+ln -sf ci/android_release android_release

dev/tools/envsetup.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+ET_P=$(pwd)/engine/src/flutter/bin/
+echo "Adding $ET_P to path"
+PATH=$PATH:$ET_P
+echo "Writing flutter root path to ~/.flutter_path"
+echo $PWD > ~/.flutter_path