Drop 'unknown' suffix in runtime version

[Yi Zhao]

Hi folks,


When I build gunpg in Yocto, a "-unknown" suffix appears in the gpg 
runtime version:

$ gpg --version
gpg (GnuPG) 2.5.5-unknown

This is because the configure will be re-generated by autoreconf in 
Yocto. The autogen.sh will add "-unknown" suffix to PACKAGE_VERSION.
Now I have a simple patch to remove this suffix in autogen.sh.
I wonder if there is a more appropriate way to resolve this? Thanks.



//Yi