Linux/Ubuntu support

[elton-okawa]

First of all, thank you for your amazing work! 🎉

Could you add Linux/Ubuntu support to this library?
I'm having the following errors while building https://github.com/CapSoftware/Cap that depends on this package, it seems that it's trying to load especific macos packages on linux:

@cap/desktop:dev:     Building [=======================> ] 784/805: tauri-nspane@cap/desktop:dev: error[E0463]: can't find crate for `cocoa`
@cap/desktop:dev:   --> /home/me/.cargo/git/checkouts/tauri-nspanel-47b5b83dc190123c/07b1a04/src/lib.rs:15:1
@cap/desktop:dev:    |
@cap/desktop:dev: 15 | pub extern crate cocoa;
@cap/desktop:dev:    | ^^^^^^^^^^^^^^^^^^^^^^^ can't find crate
@cap/desktop:dev: 
@cap/desktop:dev: error[E0463]: can't find crate for `objc`
@cap/desktop:dev:   --> /home/me/.cargo/git/checkouts/tauri-nspanel-47b5b83dc190123c/07b1a04/src/lib.rs:16:1
@cap/desktop:dev:    |
@cap/desktop:dev: 16 | pub extern crate objc;
@cap/desktop:dev:    | ^^^^^^^^^^^^^^^^^^^^^^ can't find crate
@cap/desktop:dev: 
@cap/desktop:dev: error[E0463]: can't find crate for `objc_foundation`
@cap/desktop:dev:   --> /home/me/.cargo/git/checkouts/tauri-nspanel-47b5b83dc190123c/07b1a04/src/lib.rs:17:1
@cap/desktop:dev:    |
@cap/desktop:dev: 17 | pub extern crate objc_foundation;
@cap/desktop:dev:    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't find crate
@cap/desktop:dev: 
@cap/desktop:dev: error[E0463]: can't find crate for `objc_id`
@cap/desktop:dev:   --> /home/me/.cargo/git/checkouts/tauri-nspanel-47b5b83dc190123c/07b1a04/src/lib.rs:18:1
@cap/desktop:dev:    |
@cap/desktop:dev: 18 | pub extern crate objc_id;
@cap/desktop:dev:    | ^^^^^^^^^^^^^^^^^^^^^^^^^ can't find crate
@cap/desktop:dev: 
@cap/desktop:dev:     Building [=======================> ] 784/805: tauri-nspane@cap/desktop:dev: For more information about this error, try `rustc --explain E0463`.
@cap/desktop:dev:     Building [=======================> ] 784/805: tauri-nspane@cap/desktop:dev: error: could not compile `tauri-nspanel` (lib) due to 4 previous errors

Thanks in advance!

[ahkohd]

Hey @elton-okawa, thanks for reaching out. It's not possible to create a version of this plugin for Linux because it subclasses NSWindow to NSPanel, which are macOS-exclusive APIs.

However, I made an adjustment to Cargo.toml. The block crate was causing build failures on platforms other than macOS, so I moved it into the macOS dependencies list. That was an error on my part. When you update your project's crates (i.e cargo update), the build issue on Linux should be resolved.

See commit: 8763909