buildtools: Remove libunwind from buildtools/DEPS

If your project DEPS's in buildtools and needs libunwind, edit your
toplevel DEPS file to have something like

  'libunwind_revision':    'a2cc4f8c554dedcb0c64cac5511b19c43f1f3d32',

in its `vars =` section, and an entry similar to

  'src/buildtools/third_party/libunwind/trunk':
    Var('chromium_git') +
    '/external/github.com/llvm/llvm-project/libunwind.git' + '@' +
    Var('libunwind_revision'),

in its `deps =` section. Add libunwind_revision to your autoroller
that rolls //build and //tools/clang etc.

Since libunwind is only used in Fuchsia builds and for chrome/android's
sampling profiler, it's possible that no projects other than chromium
actually need this.

This makes it possible to set up an autoroller for libunwind for chromium.

Bug: 1177288
Change-Id: I7a59f11b015acc98b65f4b87a9277a5a3028328d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2713283
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Cr-Commit-Position: refs/heads/master@{#856453}
GitOrigin-RevId: 94da3c1ef4f91efc704a5ac44878029bc9fedc8c
1 file changed