gn: Fix bootstrap after https://crrev.com/c/4666325

Adjust paths in the bootstrap script and handwritten libc++.ninja after
libc++ and libc++abi were moved from //buildtools to //third_party.

//buildtools/third_party/libc++ is still included because of
__config_site.

Bug: 1458042
Change-Id: Ica338a6f828f22fa71ce09e737136d2f7bd45aa6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4800457
Auto-Submit: Raphael Kubo Da Costa <raphael.kubo.da.costa@intel.com>
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1186656}
NOKEYCHECK=True
GitOrigin-RevId: 60a4e9d85f652fa4c371a319eb8b45841944ae01
2 files changed
tree: 9ea04b44b9aaef26757812db30ae4715154334cc
  1. bootstrap/
  2. tutorial/
  3. README.md
  4. roll_gn.py
README.md

GN now lives at https://gn.googlesource.com/.

To roll the latest version of GN into Chromium:

  1. Create a new Git branch.
  2. Run python tools/gn/roll_gn.py; this will modify //DEPS and //buildtools/DEPS to point to the most recent revision of GN and create a commit with a list of the changes included in the roll.
  3. Run git-cl upload to upload the commit as a change for review.

If you don't want to roll to the latest version, you can specify the SHA-1 to roll to use as an argument to the script, and it will be used instead.