[gentoo-devhelp] How do I get the major+minor version of a package?

[Nikos Chantziaras]

Let's suppose that $PV is "2.5.1". How would I get the "2.5" in it in an 
ebuild?  I know about ${PV:0:3}, but this breaks if $PV is, say, 
"2.13.1".  In that case, I would get "2.1" instead of "2.13".

I've looked in the various eclasses if there's some utility function 
that get me the major and minor version, but can't find anything.