hp2ps: fix invalid PostScript for names with parentheses

Authored by bgamari on Jul 16 2016, 5:14 PM.

Description

hp2ps: fix invalid PostScript for names with parentheses

The names in the .hp files may contain un-matched opening parentheses,
so escape them.

GHC Trac: Trac #9517

Reviewers: bgamari, austin

Reviewed By: bgamari, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2398

GHC Trac Issues: Trac #9517