Refactor the logic for the hardware.html page to dynamically check out share/man/man4 from the relevant branch if it does not exist.
Key changes:
- Moves the 'THISRELEASE' definiton to Makefile.inc to reduce duplication.
- Evaluates the branch (such as -CURRENT versus -STABLE) to determine the branch to checkout.
- Adds a new src-checkout target to hardware/Makefile, which is added automatically to the target dependency list if the MAN4DIR does not exist.
This should eliminate needing to update the webupdate script to account for each branch share/man/man4 directory to generate the hardware page.