Rust bump
Builds on pmmx/x86_64/ppc64/aarch64. Successfully builds Firefox.
Still fails 17 tests on ppc32, but the ICE has been fixed:
[run-make] run-make-fulldeps/exit-code
[run-make] run-make-fulldeps/extern-fn-generic
[run-make] run-make-fulldeps/extern-fn-struct-passing-abi
[run-make] run-make-fulldeps/extern-fn-with-packed-struct
[run-make] run-make-fulldeps/extern-fn-with-union
[run-make] run-make-fulldeps/issue-25581
[run-make] run-make-fulldeps/relocation-model
[run-pass] run-pass/extern/extern-pass-TwoU16s.rs
[run-pass] run-pass/extern/extern-pass-TwoU32s.rs
[run-pass] run-pass/extern/extern-pass-TwoU64s.rs
[run-pass] run-pass/extern/extern-pass-TwoU8s.rs
[run-pass] run-pass/extern/extern-pass-empty.rs
[run-pass] run-pass/foreign/foreign-fn-with-byval.rs
[run-pass] run-pass/issues/issue-28676.rs
[run-pass] run-pass/structs-enums/struct-return.rs
[run-pass] run-pass/threads-sendsync/thread-local-extern-static.rs
[run-pass] run-pass/union/union-c-interop.rs