cpal

Remove once_cell dependency #757

Job	Run time
clippy-test	46s
ubuntu-test	55s
linux-check-and-test-armv7	1m 40s
cargo-publish	0s
asmjs-wasm32-test (asmjs-unknown-emscripten)	1m 2s
asmjs-wasm32-test (wasm32-unknown-emscripten)	1m 0s
wasm32-wasi-test (wasm32-wasi)	25s
windows-test (x86_64)	3m 55s
windows-test (i686)	4m 45s
android-check	37s
android-apk-build	1m 42s
ios-build	4m 53s
rustfmt-check	5s
macos-test	2m 17s
wasm32-bindgen-test (wasm32-unknown-unknown)	27s
wasm-beep-build	17s
	24m 46s

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