Automate GCC driver wrapper

Authored by Phyx on Dec 10 2016, 3:13 PM.

Description

Automate GCC driver wrapper

Summary:
Everytime we upgrade the GCC version this wrapper needed updating.
This is a big fragile and we kept forgetting it.

Instead automate it so we don't have to worry about it.

Test Plan: ./validate

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie, #ghc_windows_task_force

Differential Revision: https://phabricator.haskell.org/D2820

GHC Trac Issues: Trac #12871