run-make: add a //@ needs-symlink directive over //@ ignore-windows

[jieyouxu]

symlinks are a priviledged operation on Windows, but we should not straight up //@ ignore-windows as the CI runners have symlinks enabled, and so might the contributor on their local Windows machines. Instead, we should try to do what stdlib does here:

rust/library/std/src/fs/tests.rs

Lines 68 to 85 in 5c84886

	// Several test fail on windows if the user does not have permission to
	// create symlinks (the `SeCreateSymbolicLinkPrivilege`). Instead of
	// disabling these test on Windows, use this function to test whether we
	// have permission, and return otherwise. This way, we still don't run these
	// tests most of the time, but at least we do if the user has the right
	// permissions.
	pub fn got_symlink_permission(tmpdir: &TempDir) -> bool {
	if cfg!(not(windows)) || env::var_os("CI").is_some() {
	return true;
	}
	let link = tmpdir.join("some_hopefully_unique_link_name");
	match symlink_file(r"nonexisting_target", link) {
	// ERROR_PRIVILEGE_NOT_HELD = 1314
	Err(ref err) if err.raw_os_error() == Some(1314) => false,
	Ok(_) | Err(_) => true,
	}
	}

Thanks to @ChrisDenton for pointing this out to me!

[jieyouxu]

Wait Chris already added this in #126862 and I was the one to review that PR 💀 Nevermind lol.