[main]: backport `Add posix_spawn{_file_actions_t,attr_t} on Android`

[tesuji]

Backport #3690 Close #3709 Close https://github.com/rust-lang/libc/issues/3608, close https://github.com/rust-lang/libc/issues/3677

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[tesuji]

r? @the8472

[tgross35]

I am going to close this in favor of https://github.com/rust-lang/libc/pull/3809, which resolves conflicts and includes the cherry pick message for crosslinking. (doesn't matter but this isn't technically a backport fwiw).

Going forward we will have all PRs just target main, then we can cherry pick to 0.2.