The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5eea716fd5c781edcdf52fb34459867236c837a7

commit 5eea716fd5c781edcdf52fb34459867236c837a7
Author: Scott Graham <scottmg@chromium.org>
Date: Thu Nov 23 01:59:17 2017

GN: Fix references to lib_[dir_]prefix, which should be lib_[dir_]switch

Bug:  788007 
Change-Id: I86de75ca303b66227db170021bdfd7fb50a61811
Reviewed-on: https://chromium-review.googlesource.com/786175
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518820}
[modify] https://crrev.com/5eea716fd5c781edcdf52fb34459867236c837a7/tools/gn/docs/reference.md
[modify] https://crrev.com/5eea716fd5c781edcdf52fb34459867236c837a7/tools/gn/function_toolchain.cc
[modify] https://crrev.com/5eea716fd5c781edcdf52fb34459867236c837a7/tools/gn/variables.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/mini_chromium/+/a70db15bf9985b124c1805c401d7c384a7195845

commit a70db15bf9985b124c1805c401d7c384a7195845
Author: Scott Graham <scottmg@chromium.org>
Date: Tue Nov 28 00:10:55 2017

Improvements to GN build config

- Basic implementation of solink_module tool
- Further uniquize the .o names, as in Crashpad, some .cc files are
  built multiple times with different #defines (e.g.
  crashpad_info_size_test_module.cc near
  https://chromium.googlesource.com/crashpad/crashpad/+/master/snapshot/BUILD.gn#286)
- Set lib_switch and lib_dir_switch
- Remove probably-not-working is_clang GN variable.
- Refer to fuchsia SDK/clang that are now downloaded in runhooks.

Bug: crashpad:79, crashpad:196,  chromium:788007 
Change-Id: I795b7a5ad211076f38424798b37350dec8a1eb14
Reviewed-on: https://chromium-review.googlesource.com/786676
Reviewed-by: Mark Mentovai <mark@chromium.org>

[modify] https://crrev.com/a70db15bf9985b124c1805c401d7c384a7195845/build/BUILD.gn
[modify] https://crrev.com/a70db15bf9985b124c1805c401d7c384a7195845/build/BUILDCONFIG.gn

Online .md does are updated already by the CL, `gn help` won't be updated until gn rolls, but I'm not going to do that just for this small fix.