Bug 1472101 - Part 0: Add a script to build auto-generated BinAST code. r=Yoric

js/src/frontend/binsource/build.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+cargo run -- \
+      ../BinSource.webidl_ \
+      ../BinSource.yaml \
+      --out-class ../BinSource-auto.h    \
+      --out-impl ../BinSource-auto.cpp   \
+      --out-token ../BinToken.h