Failure to build zune-jpeg@0.4.21 crate for ruffle

Using --keep-going to workaround https://github.com/rust-lang/rustc_codegen_gcc/issues/790.

$ git clone https://github.com/ruffle-rs/ruffle
$ git rev-parse HEAD
1aad9ba00001103b7c1309fff3e7e3f650cd5d17
$ cargo build --jobs 1 --keep-going
   Compiling zune-jpeg v0.4.21
libgccjit.so: error: : the last argument must be an 8-bit immediate
libgccjit.so: error: : the last argument must be an 8-bit immediate
error: failed to build archive at `/tmp/ruffle/target/debug/deps/libzune_jpeg-74f383d3ad5956b7.rlib`: failed to open object file: No such file or directory (os error 2)

fatal runtime error: failed to initiate panic, error 5, aborting
error: could not compile `zune-jpeg` (lib) due to 1 previous error

Caused by:
  process didn't exit successfully: `rustc --crate-name zune_jpeg --edition=2021 /home/sam/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/zune-jpeg-0.4.21/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=186 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --warn=unexpected_cfgs --check-cfg 'cfg(fuzzing)' --cfg 'feature="default"' --cfg 'feature="neon"' --cfg 'feature="std"' --cfg 'feature="x86"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("default", "log", "neon", "std", "x86"))' -C metadata=03d7898f766feb93 -C extra-filename=-74f383d3ad5956b7 --out-dir /tmp/ruffle/target/debug/deps -L dependency=/tmp/ruffle/target/debug/deps --extern zune_core=/tmp/ruffle/target/debug/deps/libzune_core-5fd43cb02ab9d22a.rmeta --cap-lints allow --cfg=web_sys_unstable_apis` (signal: 6, SIGABRT: process abort signal)

$ rustc -vV
rustc 1.91.0-nightly (21cd82aa6 2025-10-08) (gentoo)
binary: rustc
commit-hash: 21cd82aa6363f7ceaebefafc528e62124267461c
commit-date: 2025-10-08
host: x86_64-unknown-linux-gnu
release: 1.91.0-nightly

This is with the rust 1.91.0 beta from 20251009 and github.com/rust-lang/rust from b93730ce97c738bdb9209aa973d3fc6fd4ce1d81.

Reproduce the failure with the reported ruffle commit using cargo build --jobs 1 --keep-going and the listed Rust versions. Start by tracing the zune-jpeg compilation failure through rustc_codegen_gcc and libgccjit; done means the crate builds without the immediate-value errors, missing archive, or abort.