Support QNX OS without RUSTFLAGS #493

Job	Run time
CheckTargets	1m 17s
Check (aarch64-apple-ios)	30s
Clippy	12s
Docs	8s
Check (aarch64-apple-tvos)	30s
MinimalVersions (ubuntu-latest)	18s
Check (aarch64-unknown-openbsd)	32s
MinimalVersions (macos-latest)	24s
Check (arm64_32-apple-watchos)	29s
MSRV (ubuntu-latest)	11s
Nightly	18s
MinimalVersions (windows-latest)	44s
Check (armv7-sony-vita-newlibeabihf)	32s
MSRV (macos-latest)	15s
Check (sparcv9-sun-solaris)	30s
MSRV (windows-latest)	40s
Rustfmt	5s
Check (x86_64-pc-solaris)	29s
Sanitizer (address)	43s
Check (x86_64-unknown-dragonfly)	31s
Sanitizer (leak)	37s
Test (ubuntu-latest)	41s
TestPoll	31s
Check (x86_64-unknown-openbsd)	29s
Sanitizer (memory)	1m 8s
Sanitizer (thread)	43s
TestWakerPipe	26s
Test (macos-latest)	41s
Test (windows-latest)	2m 34s
Passed	1s
	17m 9s

Provide feedback