Tracking Issue: Problems with Zig

[ikskuh]

Bugs:

• unreachable .addrspacecast in Builder.zig:castConstAssumeCapacity is reachable ziglang/zig#17219 (was solved in llvm: add const addrspace cast ziglang/zig#16684, wait for 0.11.1)
• [avr-freestanding-none] LLVM ERROR: Expected a constant shift amount! ziglang/zig#16417
• Build fails without error message when taking the address of extern anyopaque value ziglang/zig#16627
• Implement compiler_rt for AVR #42
• ld.lld: warning: Linking two modules of different target triples ... arm-unknown-linux-musleabihf vs armv6kz-unknown-linux-musleabihf ziglang/zig#14962

Features:

• Allow passing a custom os package to std ziglang/zig#10392
• Proposal: Link-time initialization of globals ziglang/zig#9512
• Bug: "unable to evaluate constant expression" when depending on symbol address ziglang/zig#6789 / Comptime Memory and Type Punning Rules ziglang/zig#9646
• Zig-based alternative to linker scripts ziglang/zig#3206
• Behaviour tests for AVR backend ziglang/zig#17220

Nice-to-have:

• Create Parallax Propeller backend ziglang/zig#7202