[packages/rust] (5 commits) ...Release 3 (by relup.sh)

[atler]

Summary of changes:

  4c9ef3a... disable rust-lld during bootstrap build (*)
  089ea8b... switch to specrustflags (*)
  37c305c... set RUSTFLAGS before install (*)
  9d0b04c... rust-lld is stable only on x86_64 (*)
  c2c2187... Release 3 (by relup.sh)

(*) This commit already existed in another branch; no separate mail sent