aarch64 Linux build + runtime: XLookupString mismatch, max_color_attachments limit, lib name

[ElYaiko]

Three blockers to build and run on this platform:

1. XLookupString type mismatch (build error)

error[E0308]: mismatched types
  --> src/lib.rs:397:29
   |
397 |   buf.as_mut_ptr() as *mut i8,
   |                     ^^^^^^^^^^ expected `*mut u8`, found `*mut i8`

native/linux/src/lib.rs:397 casts buf.as_mut_ptr() (which is *mut u8) to *mut i8, but on aarch64 Linux c_char = u8 (ARM C ABI defines char as unsigned). Rust 1.95+ on Fedora 42 correctly sets c_char per-target. The x11 crate's XLookupString takes *mut c_char = *mut u8 here, so the cast is wrong.

Fix: remove the as *mut i8 cast — just use buf.as_mut_ptr().

2. max_color_attachments: requested 8, allowed: 5 (runtime crash)

thread panicked at src/lib.rs:582 — Failed to create device: 
RequestDeviceError { inner: Core(LimitsExceeded(FailedLimit { 
  name: "max_color_attachments", requested: 8, allowed: 5 
}))}

This platform caps at 5 color attachments. wgpu::Limits::default() returns downlevel_defaults() which hardcodes max_color_attachments: 8. The engine uses Limits::default() at native/linux/src/lib.rs:565 as the base for required_limits instead of adapter.limits().

Fix: replace wgpu::Limits::default() with adapter.limits() — capping limits to what the adapter actually supports.

3. Cargo.toml lib name mismatch

native/linux/Cargo.toml names the lib bloom_linux, but perry's package.json expects libbloom_linux_bundled.a, so perry fails with:

Error: Native library libbloom_linux_bundled.a not found after building bloom/core crate

Fix: rename lib in Cargo.toml:3 → name = "bloom_linux_bundled".

---

Environments tested:

• OS: Fedora Asahi Remix 42 (aarch64)
• GPU: Apple M1 (G13G B1) via Asahi Linux Vulkan driver
• Rust: 1.95.0 (Fedora 1.95.0-1.fc42)
• @bloomengine/engine: 0.4.3
• @perryts/perry: 0.5.x

[proggeramlug]

Thanks for the report @ElYaiko I'll check this out today and get back to you (same with your other ticket)