cdylib cleanup #1052

Job	Run time
Build and test (stable, ubuntu-latest, x86_64-unknown-linux-gnu)	1m 3s
Build and test (msrv, ubuntu-latest, x86_64-unknown-linux-gnu)	59s
Build and test (beta, ubuntu-latest, x86_64-unknown-linux-gnu)	1m 7s
QEMU build & test (stable, ubuntu-latest, s390x-unknown-linux-gnu, s390x-linux-gnu-gcc)	1m 0s
Clippy	18s
cargo-c dynamic library	17s
Build and test (stable, macos-latest, x86_64-apple-darwin)	1m 26s
QEMU build & test (stable, ubuntu-latest, i686-unknown-linux-gnu, i686-linux-gnu-gcc)	53s
Clippy (--no-default-features --features="c-allocator")	17s
Build and test (stable, macos-14, aarch64-apple-darwin)	1m 17s
Clippy (--no-default-features --features="rust-allocator")	21s
Build and test (stable-x86_64-gnu, windows-2022, x86_64-pc-windows-gnu)	1m 59s
Smoke-test fuzzing targets (stable, macos-14, aarch64-apple-darwin)	2m 39s
Smoke-test fuzzing targets (default)	2m 45s
Smoke-test fuzzing targets (c-allocator)	2m 34s
vanilla dynamic library	14s
Miri	1m 41s
Smoke-test fuzzing targets (rust-allocator)	2m 34s
run flate2 test suite	28s
wasm32	45s
	24m 37s

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