To create the sd_device object of a driver, the function
sd_device_new_from_subsystem_sysname() requires "drivers" for subsystem
and e.g. "pci:iwlwifi" for sysname. Similarly, sd_device_new_from_device_id()
also requires driver subsystem. However, we have never provided a
way to get the driver subsystem ("pci" for the previous example) from
an existing sd_device object.
Let's introduce a way to get driver subsystem.
This tries to add information about when each option was added. It goes
back to version 183.
The version info is included from a separate file to allow generating it,
which would allow more control on the formatting of the final output.
