polkit incorrect os_type used when building

[jrripple]

I noticed when building polkit for an imx8 processor that the polkit-1 file (which is placed/usr/lib/pam.d/polkit-1) has different contents depending on the os_type variable. This is an issue because when I build the polkit recipe for the imx8 processor, the polkit source seems to be dynamically checking what os to use by looking at files in /etc of the build machine not the target: https://github.com/polkit-org/polkit/blob/main/meson.build#L291

This doesn't seem like the correct behavior for a bitbake build. If the polkit source doesn't change then at the very least a default should be set in the polkit recipe with EXTRA_OEMESON += "-Dos_type=${DEFAULT_POLKIT_OS}".