Don't let remove_dir_all recursively remove a symlink

[pitdicker]

See #29412

[rust-highfive]

r? @alexcrichton

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[alexcrichton]

This logic looks pretty similar between here and windows, perhaps it could be lifted to std::fs and leave the recursive bits to the platform-specific modules?

[pitdicker]

The Windows version is similar but a bit tricky. It uses rmdir() so it can only remove directory symlinks and not file symlinks. Unix just uses unlink(). But I don't mind if we make the distinction here or in std::fs.

[alexcrichton]

Oh right, yeah, good point!

[alexcrichton]

Looks good to me, thanks @pitdicker!

[alexcrichton]

@bors: r+ d47036c

[bors]

⌛ Testing commit d47036c with merge 227f399...

[pitdicker]

O, I am very sorry. I only tested with symlinking permissions, not also without. The build will fail

[alexcrichton]

@bors: r+ d1bfe9b

[bors]

⌛ Testing commit d1bfe9b with merge e06f692...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-mac-ios-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt