The use flags belong to csync, the way they are designed, it's even worse because if csync has samba, this requires to disable samba as well. Since there are "automagic" in the ebuild, this is simply wrong, so please get rid of them, thank you very much.
I made the change as a response to bug 433165. I concede that changing the = deps to ? deps might be better, but other than that, what is your solution to that bug?
My suggestion would be to just tell the user that they have to change csync USE flags if they want to support given protocols.
(In reply to comment #1) > what is your solution to that bug? einfo in pkg_postinst
Fixed in 1.1.2 in the KDE overlay with ! has_version checks + elogs in pkg_postinst, which I will move to the tree later this week (and then will drop the older versions)
Fixed in tree as of a couple days ago.