Add install script to optionally build from source

Closes #191, closes #157

package.json

@@ -23,12 +23,16 @@
     "wrapper.js",
     "package.json",
     "README.md",
-    "LICENSE"
+    "LICENSE",
+    "src",
+    "scripts/build-from-source.js",
+    "binding.gyp"
   ],
   "scripts": {
     "prebuild": "prebuildify --napi --strip --tag-libc",
     "format": "prettier --write \"./**/*.{js,json,md}\"",
     "build": "node-gyp rebuild -j 8 --debug --verbose",
+    "install": "node scripts/build-from-source.js",
     "test": "mocha"
   },
   "engines": {

scripts/build-from-source.js

@@ -0,0 +1,13 @@
+#!/usr/bin/env node
+
+const {spawn} = require('child_process');
+
+if (process.env.npm_config_build_from_source === 'true') {
+  build();
+}
+
+function build() {
+  spawn('node-gyp', ['rebuild'], { stdio: 'inherit', shell: true }).on('exit', function (code) {
+    process.exit(code);
+  });
+}