Always use -Xlinker for -rpath

Authored by niteria on Jan 21 2017, 11:59 AM.

Description

Always use -Xlinker for -rpath

Currently we use -Wl which takes a list of
comma-separated options. Unfortunately that
breaks when you use it with -rpath and
a path that has commas in them.
Buck, the build system, produces paths with
commas in them.

-Xlinker doesn't have this disadvantage
and as far as I can tell is supported by
both gcc and clang. Anecdotally nvcc
supports -Xlinker, but not -Wl.

Test Plan: ./validate, harbourmaster

Reviewers: nomeata, simonmar, austin, bgamari, hvr

Reviewed By: simonmar, bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2971