[Pkg-rust-maintainers] Bug#1079302: Bug#1079302: rust-image: please provide feature avif-encoder

[Peter Green]

> - rust-imgref's autopkgtest failure on i386.

This one was pretty trivial, the bench was trying to accumulate
values into accumulators that were too small. Changing the
accumulators from usize to u64 fixed it.

> - rust-fallible-collections has failing build tests on 32-bit
> architectures. 

This one was not so trivial.

The test was creating a broken Vec which appeared to have a size
of isize::MAX, but did not actually have that much backing memory,
then tried to clone it, expecting the clone to fail with an
out of memory error.

However, on some 32-bit systems (and especially on 64-bit
userlands running on 64-bit kernels), it's actually possible to
make an allocation of size isize::MAX, so the clone call
starts actually trying to clone the broken Vec. Which, as
one would expect, segfaults.

I've skipped the test in question and another similar test
on 32-bit architectures.