pkgsrc firefox91 - rust-fu needed for borrowed value

[David Brownlee <abs%absd.org@localhost>]

Attempting to build firefox91 with rust1.64 chokes with the below
error, presumably due to stricter borrow checking. The affected file
is completely different in firefox102, and I know enough rust to
recognise it two times out of three...

So the options seem to be:
a) Have someone with rust-fu to take a look
b) Add a rust163 package to build firefox91
c) Drop firefox91

David

error[E0597]: `desc_set` does not live long enough
    --> gfx/wgpu/wgpu-core/src/device/mod.rs:1795:26
     |
1795 |                     set: desc_set.raw_mut(),
     |                          ^^^^^^^^^^^^^^^^^^ borrowed value does
not live long enough
...
1816 |     }