rcook authored Aug 30, 2016 and Ben Gamari committed Aug 31, 2016

In outHsLine, paths passed to construct invocations of hsc_line must be
escaped twice in order to generate a properly escaped string literal
that will end up in the eventual LINE pragma emitted by this code. This
is especially important on Windows paths, where backslashes would
otherwise be treated as C escape sequences and result in the incorrect
Windows paths.

Adds test case to verify that hsc2hs properly escapes file paths in LINE
pragmas

Updates the hsc2hs submodule.

See https://ghc.haskell.org/trac/ghc/ticket/12504

Reviewers: erikd, hvr, austin, bgamari, Phyx

Reviewed By: erikd, Phyx

Subscribers: thomie, Phyx, mpickering

Differential Revision: https://phabricator.haskell.org/D2478

GHC Trac Issues: #12504