Backport build.rs fixes to 2.x. #1732

Job	Run time
Check Cross-Compilation on Rust nightly on Windows (nightly)	1m 40s
Check Cross-Compilation on Rust nightly (nightly)	1m 59s
Check Cross-Compilation (stable)	1m 13s
Check Cross-Compilation on Windows (stable)	55s
Check Cross-Compilation (beta)	1m 25s
Fuzz Targets	53s
Check Cross-Compilation on Windows (beta)	52s
Rustfmt	4s
Test linux-raw support (ubuntu)	29s
Test (msrv)	2m 18s
Test linux-raw support (ubuntu-20.04)	31s
Test (stable)	25s
Test on Musl (ubuntu)	43s
Test (windows-latest)	1m 18s
Test (windows-2019)	1m 14s
Test with Rust nightly (ubuntu)	32s
Test (macos-latest)	30s
Test with Rust nightly (windows)	1m 31s
Test (macos-12)	43s
Test (beta)	31s
Test (ubuntu-20.04)	38s
Test (aarch64-ubuntu)	44s
	21m 8s

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