We shouldn't try compiling to aarch64-unknown-linux-gnu from
aarch64-unknown-linux-gnu, because that tends to confuse things and is
not representative of actual cross compilation usage.
Sanitizers don't seem to be present on aarch64-darwin/macOS 12 (Monterey), so they are removed from the aarch64-darwin tests.
Switching from nativeBuildInputs to buildInputs and adding cc to the deps list caused some strange error messages to go away.
On macOS, /tmp is a symlink to /private/tmp. When performing cd /tmp, and checking cwd - it won't match since it follows the symlink.
This caused test breakage on macOS but not Linux. Instead, use a folder which is not a symlink, and consistent across Linux and macOS.
