Backport build.rs fixes to 1.x. #1740

Job	Run time
Check Cross-Compilation (stable)	51s
Check Cross-Compilation (beta)	52s
Rustfmt	3s
Check Cross-Compilation on Rust nightly (nightly)	1m 23s
Check Cross-Compilation on Windows (stable)	3m 13s
Check Cross-Compilation on Windows (beta)	1m 29s
Check Cross-Compilation on Rust nightly on Windows (nightly)	1m 48s
Test (stable)	20s
Test (windows-latest)	2m 1s
Test linux-raw support (ubuntu)	24s
Test (windows-2019)	2m 9s
Test linux-raw support (ubuntu-20.04)	23s
Test (msrv)	1m 50s
Test (macos-latest)	30s
Test (macos-12)	44s
Test (beta)	29s
Test on Musl (ubuntu)	31s
Test (ubuntu-20.04)	26s
Test with Rust nightly (ubuntu)	26s
Test with Rust nightly (windows)	1m 14s
Test (aarch64-ubuntu)	2m 22s
Fuzz Targets	47s
	24m 15s

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