Release master as 0.4.2 on crates.io?

[gz]

I think due to the dependency of uefi-services on uefi I can't easily use uefi from master with uefi-services from crates.io.
(If you know a good work-around let me know)

[GabrielMajeri]

I'm trying to fix building on the latest nightlies, but currently I'm stuck on this issue related to a missing probestack function.

rust-lang/compiler-builtins#335 was merged

[GabrielMajeri]

It will take a while for a new compiler-builtins version to be released, but I'll go ahead and publish a new version of the crate.