pkg-config-wrapper: use system_libdir for libpath

pkg-config-wrapper: use system_libdir for libpath

We already have a variable for tracking the system libdir name in the
gyp files, so let's use that instead of hardcoding the logic based on
the arch.

BUG=chromium:219015
TEST=`cbuildbot amd64-generic-tot-chrome-pfq-informational` works

[vapier, 2014-04-22 01:55:24]

see the main CL https://codereview.chromium.org/244593002/

[Torne, 2014-04-22 09:58:52]

I don't really know anything about this, but from the look of it you're
modifying the input and output for an emacs syntax hilighting test.

Have you actually run the test? The output file appears to have loads of
line/column numbers in it, and I'm guessing that changing the text without
regenerating this golden output is going to make it fail.

Do you even need to change this at all? It doesn't seem like it's necessary to
update this.

[vapier, 2014-04-22 14:17:24]

I have no idea. I was just grepping for the wrapper. I don't use emacs so I
can't really test.

if you think it's unnecessary, it's easy for me to drop.

[Torne, 2014-04-22 15:00:19]

On 2014/04/22 14:17:24, vapier wrote:
> I have no idea. I was just grepping for the wrapper. I don't use emacs so I
> can't really test.
> 
> if you think it's unnecessary, it's easy for me to drop.

I don't use emacs either and running the test needs some lisp package I don't
have, so yeah.

I'd just abandon this change. This gyp file is not ever used to build anything;
it's just there as a test for the emacs syntax hilighting, so as long as it's
valid syntax it doesn't matter whether it actually *works*. ;)