rust-tempfile-3 update to 3.2.0 breaks sequoia build

[Hartmut Goebel]

Hi Nicolas,

building sequoia is currently broken in master with
"syn::export::ToTokens" not found.

I tracked this down to 6513650d40f74 "gnu: rust-tempfile-3: Update to
3.2.0." (2021-02-16). The updated package also updates some
dependency-requirements: cfg-if 0.1 -> 1, rand 0.7 -> 0.8 and
redox-syscall 0.1 -> 0.2.

While in theory - according to semantic versioning -, updating 3.1.x to
3.2.x should not any effect on others packages, this updates has :-(

I tried building with rust-tempfile-3.1, with no success - this fails
with "rand::rngs::OsRng" missing. Updating rust-rand-core-0.6 to 0.6.2
(since 0.6.1 was yanked), did not help either - then I gave up.

Any ideas how to make sequoia build again?

-- 
Regards
Hartmut Goebel

| Hartmut Goebel          | h.goebel@crazy-compilers.com               |
| www.crazy-compilers.com | compilers which you thought are impossible |