rio 0.1.12 fails to build on cross targets

[tranzystorekk]

Found when building rio for Void Linux https://github.com/void-linux/void-packages/actions/runs/10758124870/job/29833009268?pr=52138

error[E0308]: mismatched types
   --> rio-window/src/platform_impl/linux/x11/ime/context.rs:175:13
    |
175 | /             mem::transmute::<
176 | |                 usize,
177 | |                 unsafe extern "C" fn(*mut x11_dl::xlib::_XIM, *mut i8, *mut i8),
178 | |             >(preedit_start_callback as usize)
    | |______________________________________________^ expected `u8`, found `i8`
    |
    = note: expected fn pointer `unsafe extern "C" fn(_, *mut u8, *mut u8)`
               found fn pointer `unsafe extern "C" fn(_, *mut i8, *mut i8)`

[orhun]

#657 potentially fixes this.

[raphamorim]

@orhun left some comments on your PR, the problem with that fix is that actually would break for other builds with different targets (if i am not mistaken at least, XPointer has variation per target). @tranzystorekk could you test again with latest main? ff3afb7

[tranzystorekk]

Tested with these changes and rio builds fine! 😁

[raphamorim]

Thank you! closing this issue 👌