Make Linux GN build's cflags match GYP's

Make Linux GN build's cflags match GYP's

This is for the base shared library target on desktop Linux.

The remaining difference on Linux is that GYP's base build specifies -Wno-write-strings on Linux. This dates back to the first GYP file. I don't know why we would specify this for only base, and it seems not to trigger any warning without this flag, so I didn't add it.

This changes the pkg-config invocation from --libs to --libs-only-L and --libs-only-l. The output seems slightly different (--libs was producing an extra --export-dynamic for gmodule-2.0 that aren't present when invoking the other way, which is what the GYP build does).

R=thakis@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=252409

[Nico, 2014-02-19 22:03:28]

lgtm

Maybe remove -Wno-write-strings from gyp too?

[brettw, 2014-02-20 23:02:41]

Committed patchset #2 manually as r252409 (presubmit successful).