[yocto] Buggy busybox update 1.94.4 => 1.20.2

[Axel Beierlein]

Two questions from a Newbie on Yocto:

I get compiling Errors in Busybox from a new clone of the Yocto Git Repo.

I have to change the name of the .bbappend File from 1.94.4 to 1.20.2
and also the directory to get a working tree.

And in the 1.94.4.bbappend File. What means ${P} after the THISDIR?
In the Documentation i read something about ${THISDIR}/${PN} and not
${P} is this a mistake or do i understand something wrong?

Regards

Axel