Make handle_options public again.

compiler/rustc_driver_impl/src/lib.rs

@@ -1184,7 +1184,11 @@ fn print_flag_list<T>(
 ///
 /// So with all that in mind, the comments below have some more detail about the
 /// contortions done here to get things to work out correctly.
-fn handle_options(handler: &EarlyErrorHandler, args: &[String]) -> Option<getopts::Matches> {
+///
+/// This does not need to be `pub` for rustc itself, but @chaosite needs it to
+/// be public when using rustc as a library, see
+/// <https://github.com/rust-lang/rust/commit/2b4c33817a5aaecabf4c6598d41e190080ec119e>
+pub fn handle_options(handler: &EarlyErrorHandler, args: &[String]) -> Option<getopts::Matches> {
     if args.is_empty() {
         // user did not write `-v` nor `-Z unstable-options`, so do not
         // include that extra information.