Add no-std support #298

Job	Run time
msys2-test	2m 0s
cross-ios-build (stable, x86_64-apple-ios)	17s
cross-ios-build (nightly, aarch64-apple-ios)	17s
cross-ios-build (stable, aarch64-apple-ios)	19s
cross-ios-build (nightly, x86_64-apple-ios)	21s
bare-cross-build (nightly, x86_64-unknown-fuchsia)	30s
bare-cross-build (nightly, wasm32-unknown-unknown)	25s
bare-cross-build (nightly, x86_64-unknown-redox)	32s
bare-cross-build (nightly, x86_64-unknown-haiku)	32s
no-std-build-test	27s
bare-cross-build (nightly, x86_64-unknown-openbsd)	35s
windows-test (stable, x86_64-pc-windows-gnullvm)	3m 0s
windows-test (nightly, i686-pc-windows-gnu)	1m 12s
windows-test (nightly, x86_64-pc-windows-gnullvm)	1m 25s
windows-test (stable, i686-pc-windows-gnu)	1m 36s
native-test (1.81.0, windows-latest)	1m 12s
native-test (stable, ubuntu-latest)	20s
native-test (nightly, windows-latest)	1m 1s
native-test (stable, macOS-latest)	1m 11s
native-test (1.81.0, ubuntu-latest)	21s
native-test (1.81.0, macOS-latest)	1m 17s
native-test (nightly, macOS-latest)	1m 2s
native-test (stable, windows-latest)	1m 10s
native-test (nightly, ubuntu-latest)	21s
	21m 23s

Provide feedback