pkg-config.py should use --libs instead

pkg-config.py should use --libs instead of --libs-only-l --libs-only-L

When specifying both --libs-only-l and --libs-only-L to
pkg-config, the results from the latter are not included.
This feels like a bug in pkg-config, reported upstream:
https://bugs.freedesktop.org/show_bug.cgi?id=91689

Our pkg-config.py wrapper can use --libs instead of the
flags mentioned above- this includes flags from both but
maybe also some additional flags (eg -rdynamic).

BUG=522564
Committed: https://crrev.com/f5c7b1a39088d8b2f78132b5488319d986abd16a
Cr-Commit-Position: refs/heads/master@{#344260}

[Mostyn Bramley-Moore, 2015-08-19 15:37:50]

The CQ bit was checked by mostynb@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2015-08-19 15:38:04]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1291803008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1291803008/1

[Mostyn Bramley-Moore, 2015-08-19 15:41:23]

mostynb@opera.com changed reviewers:
+ brettw@chromium.org

[Mostyn Bramley-Moore, 2015-08-19 15:41:24]

@brettw: does this look OK to you?

Another option would be to call pkg-config multiple times, once with each
option, which would reduce the need to parse the flags and split them up in the
script.

[commit-bot: I haz the power, 2015-08-19 15:50:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-19 15:50:28]

Dry run: This issue passed the CQ dry run.

[brettw, 2015-08-19 16:56:56]

Do you know if the -rdynamic happens in practice or was that just an example you
made up? Currently, it looks like we'll add it to the cflags which won't work
(although this may be good because I'm not sure I want us to start specifying
-rdynamic on links where we don't already do so.

[brettw, 2015-08-19 16:57:31]

(I don't like calling it twice, pkg-config is super slow!)

[Mostyn Bramley-Moore, 2015-08-19 17:05:56]

On 2015/08/19 16:56:56, brettw wrote:
> Do you know if the -rdynamic happens in practice or was that just an example
you
> made up? Currently, it looks like we'll add it to the cflags which won't work
> (although this may be good because I'm not sure I want us to start specifying
> -rdynamic on links where we don't already do so.

The -rdynamic example is mentioned in the pkg-config manpage, but I haven't
found any instances of it in ubuntu 14.04's .pc files, nor in the cross-compiled
packages I use.

eg this doesn't give me any hits: find /usr -type f -name '*.pc' | xargs fgrep
rdynamic

[brettw, 2015-08-19 17:06:53]

Okay, sounds fine. LGTM

[Mostyn Bramley-Moore, 2015-08-19 17:11:05]

The CQ bit was checked by mostynb@opera.com

[commit-bot: I haz the power, 2015-08-19 17:11:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1291803008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1291803008/1

[Mostyn Bramley-Moore, 2015-08-19 17:11:25]

Thanks.  Added a tracking bug in case this breaks something.

[commit-bot: I haz the power, 2015-08-19 17:16:56]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-19 17:17:42]

Patchset 1 (id:??) landed as
https://crrev.com/f5c7b1a39088d8b2f78132b5488319d986abd16a
Cr-Commit-Position: refs/heads/master@{#344260}