Allow implicit function decl on A64 #1524

Job	Run time
Clippy	17s
Rustfmt	9s
Test (aarch64-apple-darwin, macos-latest, nightly)	2m 9s
Test (aarch64-unknown-linux-gnu, ubuntu-latest, nightly)	6m 38s
Test (aarch64-pc-windows-msvc, windows-latest, nightly, 1, 1)	1m 35s
Test (arm-unknown-linux-gnueabi, ubuntu-latest, nightly)	6m 22s
Test (arm-unknown-linux-gnueabihf, ubuntu-latest, nightly)	6m 23s
Test (i586-unknown-linux-gnu, ubuntu-latest, nightly)	4m 36s
Test (i686-unknown-linux-gnu, ubuntu-latest, nightly)	4m 40s
Test (powerpc-unknown-linux-gnu, ubuntu-latest, nightly)	5m 42s
Test (powerpc64-unknown-linux-gnu, ubuntu-latest, nightly)	5m 28s
Test (powerpc64le-unknown-linux-gnu, ubuntu-latest, nightly)	5m 34s
Test (riscv64gc-unknown-linux-gnu, ubuntu-latest, nightly)	6m 0s
Test (thumbv6m-none-eabi, ubuntu-latest, nightly)	3m 50s
Test (thumbv7em-none-eabi, ubuntu-latest, nightly)	3m 59s
Test (thumbv7em-none-eabihf, ubuntu-latest, nightly)	3m 50s
Test (thumbv7m-none-eabi, ubuntu-latest, nightly)	3m 46s
Test (wasm32-unknown-unknown, ubuntu-latest, nightly)	4m 23s
Test (x86_64-unknown-linux-gnu, ubuntu-latest, nightly)	4m 31s
Test (x86_64-apple-darwin, macos-13, nightly)	4m 45s
Test (i686-pc-windows-msvc, windows-latest, nightly, 1)	3m 59s
Test (x86_64-pc-windows-msvc, windows-latest, nightly, 1)	3m 58s
Test (i686-pc-windows-gnu, windows-latest, nightly-i686-gnu)	4m 53s
Test (x86_64-pc-windows-gnu, windows-latest, nightly-x86_64-gnu)	4m 43s
success	1s
	1h 42m 11s

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