[arch-general] howto only rebuild changes from existing source with makechrootpkg?

[David C. Rankin]

Guys,

  Is it possible to change and rebuild only a part of a large package with
makechrootpkg instead of having to build the entire package every time there is
a small change? Specifically, I'm working on the kio_sftp part of kdebase. Once
I build the entire kdebase package and it is in the chroot, I would like to be
able to only rebuild the changes made to the kio_sftp code instead of having to
rebuild the entire kdebase package. Something like (makepkg --noextract) so that
only the new/changed code is rebuilt from the existing code in ${srcdir}/${pkgname}.

  It's just the ability to cut down the build time I'm looking for. Is this
doable with makechrootpkg? If so, what is the best way? Subpackage? Pass
--noextract somehow?

-- 
David C. Rankin, J.D.,P.E.