use rollup-babel for bundling self (is quicker!) and include banner/version in dist files

gobblefile.js

@@ -1,17 +1,29 @@
 var gobble = require( 'gobble' );
 var fs = require( 'fs' );
 
+var version = require( './package.json' ).version;
+
+var banner = fs.readFileSync( 'src/banner.js' ).toString()
+	.replace( '${version}', version )
+	.replace( '${time}', new Date() )
+	.replace( '${commitHash}', process.env.COMMIT_HASH || 'unknown' );
+
 var src = gobble( 'src' );
 
 var node = src
-	.transform( 'rollup', {
+	.transform( 'rollup-babel', {
 		entry: 'rollup.js',
 		dest: 'rollup.js',
 		format: 'cjs',
 		external: [ 'fs' ],
-		sourceMap: true
-	})
-	.transform( 'babel' );
+		sourceMap: true,
+		banner: banner,
+		load: function ( id ) {
+			if ( ~id.indexOf( 'rollup.js' ) ) {
+				return fs.readFileSync( 'src/rollup.js', 'utf-8' ).replace( /<@VERSION@>/, version );
+			}
+		}
+	});
 
 var browserPlaceholders = {
 	fs: fs.readFileSync( 'browser/fs.js' ).toString(),
@@ -24,10 +36,14 @@ var browser = src
 		dest: 'rollup.browser.js',
 		format: 'umd',
 		moduleName: 'rollup',
+		sourceMap: true,
+		banner: banner,
 		load: function ( id ) {
+			if ( ~id.indexOf( 'rollup.js' ) ) {
+				return fs.readFileSync( 'src/rollup.js', 'utf-8' ).replace( /<@VERSION@>/, version );
+			}
 			if ( ~id.indexOf( 'fs.js' ) ) return browserPlaceholders.fs;
 			if ( ~id.indexOf( 'es6-promise' ) ) return browserPlaceholders.promise;
-			return fs.readFileSync( id ).toString();
 		}
 	});
 

package.json

@@ -14,7 +14,7 @@
     "test-coverage": "rm -rf coverage/* && istanbul cover --report json node_modules/.bin/_mocha -- -u exports -R spec test/test.js",
     "posttest-coverage": "remap-istanbul -i coverage/coverage-final.json -o coverage/coverage-remapped.json -b dist && remap-istanbul -i coverage/coverage-final.json -o coverage/coverage-remapped.lcov -t lcovonly -b dist && remap-istanbul -i coverage/coverage-final.json -o coverage/coverage-remapped -t html -b dist",
     "ci": "npm run test-coverage && codecov < coverage/coverage-remapped.lcov",
-    "build": "gobble build -f dist",
+    "build": "export COMMIT_HASH=`git rev-parse HEAD` && gobble build -f dist",
     "prepublish": "npm test",
     "lint": "eslint src"
   },

src/banner.js

@@ -0,0 +1,8 @@
+/*
+	Rollup.js v${version}
+	${time} - commit ${commitHash}
+
+	https://github.com/rollup/rollup
+
+	Released under the MIT License.
+*/

src/rollup.js

@@ -4,6 +4,8 @@ import { keys } from './utils/object';
 import SOURCEMAPPING_URL from './utils/sourceMappingURL';
 import Bundle from './Bundle';
 
+export const VERSION = '<@VERSION@>';
+
 export function rollup ( options ) {
 	if ( !options || !options.entry ) {
 		throw new Error( 'You must supply options.entry to rollup' );