build/lib/util.ts/setExecutableBit
export function setExecutableBit(pattern?: string | string[]): NodeJS.ReadWriteStream {
	const setBit = es.mapSync<VinylFile, VinylFile>(f => {
		if (!f.stat) {
			f.stat = { isFile() { return true; } } as any;
		}
		f.stat.mode = /* 100755 */ 33261;
		return f;
	});

	if (!pattern) {
		return setBit;
	}

	const input = es.through();
	const filter = _filter(pattern, { restore: true });
	const output = input
		.pipe(filter)
		.pipe(setBit)
		.pipe(filter.restore);

	return es.duplex(input, output);
}