Thomas, are you the right person to ask about glib/pkgconfig? 1) Do you know wju -export-dynamic would be necessary? and 2) If it's not what would be the right way to remove it from our ldflags given that it's in the pkgconfig in the sysroot?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f

commit 8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f
Author: Tom Anderson <thomasanderson@chromium.org>
Date: Fri Jun 01 04:28:30 2018

Don't allow dependencies to set ldflags via pkgconfig

Currently gmodule is the only package in the sysroot that sets an ldflag.  The
flag it adds is -Wl,--export-dynamic, which increases the size of nacl_helper by
~2%.  The chrome binary appears to be unaffected (possibly because a linker
script is used to limit which symbols get put into the dynamic symbol table).
Only Chromium build files should be allowed to add ldflags.

This CL adds a new global config: //build/config/linux:export_dynamic which is
removed in nacl_helper to reduce binary size.

BUG= 843317 
R=thestig,dpranke

Change-Id: Id23862483f7c4067a4a028cdc2fd19d91c0abbbe
Reviewed-on: https://chromium-review.googlesource.com/1065110
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Derek Schuff <dschuff@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563534}
[modify] https://crrev.com/8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f/build/config/BUILDCONFIG.gn
[modify] https://crrev.com/8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f/build/config/linux/BUILD.gn
[modify] https://crrev.com/8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f/build/config/linux/pkg-config.py
[modify] https://crrev.com/8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f/build/config/linux/pkg_config.gni
[modify] https://crrev.com/8b2aefd2ab65e6ab4f50aad7ab86e905bf1df51f/components/nacl/loader/BUILD.gn