Fixes needed by io_uring. #3427

Job	Run time
Check --no-default-features (nightly)	25s
Check nightly-only targets (nightly)	27s
Check selected Tier 3 platforms (nightly)	35s
Check (stable)	38s
Rustfmt	16s
Check (nightly)	36s
Check (1.63)	37s
Test rustix_use_experimental_asm (powerpc64le-linux)	39s
Test (ubuntu)	34s
Test use-libc (ubuntu)	34s
Test use-libc (i686-linux)	29s
Test use-libc (aarch64-linux)	23s
Test (ubuntu-20.04)	37s
Test use-libc (powerpc64le-linux)	22s
Test (i686-linux)	19s
Test use-libc (riscv64-linux)	34s
Test (aarch64-linux)	34s
Test use-libc (arm-linux)	32s
Test (powerpc64le-linux)	20s
Test (riscv64-linux)	18s
Test (s390x-linux)	19s
Test (arm-linux)	32s
Test (ubuntu-stable)	17s
Test (i686-linux-stable)	22s
Test (aarch64-linux-stable)	21s
Test (riscv64-linux-stable)	20s
Test (s390x-linux-stable)	19s
Test (powerpc64le-linux-stable)	19s
Test (arm-linux-stable)	33s
Test (ubuntu-1.63)	31s
Test (i686-linux-1.63)	28s
Test (aarch64-linux-1.63)	31s
Test (riscv64-linux-1.63)	31s
Test (s390x-linux-1.63)	20s
Test (powerpc64le-linux-1.63)	20s
Test (arm-linux-1.63)	21s
Test (macos-latest)	34s
Test (macos-11)	19s
Test (windows)	18s
Test (windows-2019)	20s
	17m 44s

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