tree c286b4efc6135b170094cc49d9598328adf84d09
parent f8c5cf1d5ce5f2cd71fc76be0974db85c50ba90a
author Adrian Taylor <adetaylor@chromium.org> 1588365216 -0700
committer Commit Bot <commit-bot@chromium.org> 1589302354 +0000

Cease to specify extern dirs for proc macro deps.

Previously, if we had this arrangement:

  [Rust binary]
   -> depends on ->
  [Rust proc macro]
   -> depends on ->
  [Rust library]

then the Rust library would be stored as a transitive dependency of the
Rust binary. This was unnecessary because Rust procedural macros are
complete standalone .so files, with no further references to the rlibs
from which they are composed.

The practical implication here is just a few extra unnecessary
  -Ldependency
arguments to specify where to find such rlibs.

However, subsequent commits use the list of transitive dependencies for
more purposes, and this problem becomes more serious.

Change-Id: I0310d60db1cab97fa6a808c9a08f663e53eba2ad
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/8300
Commit-Queue: Brett Wilson <brettw@chromium.org>
Reviewed-by: Brett Wilson <brettw@chromium.org>