Pass -no-canonical-prefixes to clang-cl too.

clang-cl learned this flag in https://reviews.llvm.org/rL333761 (which also has
some words on why it's not the default). #566302 was a clang roll containing
that change.

Note that we also need https://reviews.llvm.org/rL334602 for this to have
an effect in practice, and that's not rolled in yet. Once it is, goma should
be able to cache non-symbol .obj files independent of the checkout path.
(See also discussion in https://chromium-review.googlesource.com/c/chromium/src/+/1075947)

Bug: 439949,330260,712796
Change-Id: I4a9bc38e35884be03fd9898e7000938cb4782a54
Reviewed-on: https://chromium-review.googlesource.com/1099638
Reviewed-by: Reid Kleckner <rnk@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567001}
1 file changed