Use --copy-out to generate .bp file.

* The original include command now works without
  local patch or post_update.sh.
* Add missing std.diff

Bug: 171659849
Test: make
Test: tools/external_updater/updater.sh update --refresh --keep-date rust/crates/proc-macro-nested
Change-Id: Ifcacf844017ef1332f1abad6e8d47c99dfea873a
4 files changed