cpal

Improve asio sys build script #752

Job	Run time
ubuntu-test	1m 19s
rustfmt-check	17s
clippy-test	1m 20s
wasm32-bindgen-test (wasm32-unknown-unknown)	40s
asmjs-wasm32-test (asmjs-unknown-emscripten)	1m 25s
linux-check-and-test-armv7	1m 46s
asmjs-wasm32-test (wasm32-unknown-emscripten)	1m 32s
android-apk-build	1m 26s
android-check	1m 26s
cargo-publish	0s
ios-build	4m 56s
macos-test	2m 4s
wasm32-wasi-test (wasm32-wasi)	31s
wasm-beep-build	17s
windows-test (x86_64)	4m 20s
windows-test (i686)	3m 10s
	26m 29s

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