Another confusing message (when rpmb is not available) is:
$ rpm --version -ba existing.spec

Another confusing message (when rpmb is not available) is:
$ rpm --version -ba existing.spec

It\'s _quite_ confusing: e.g. Vladimir Bormotov got caught by an example too.  Well, I was stupid enough a couple of times too.

It\'s _quite_ confusing: e.g. Vladimir Bormotov got caught by an example too.  Well, I was stupid enough a couple of times too.

*** Bug 3505 has been marked as a duplicate of this bug. ***

I look at source code of rpm (4.0.4-alt37) and find this incorrect(?) string in
rpmqv.c:630

argerror("--buildroot may only be used during package builds");

may be must be: 

argerror(_("--buildroot may only be used during package builds"));

or I'm not right? May be this solve problem with this confused message...(?)

No, this message is unrelated to the problem.

To more appropriate package.

Fixed in libpopt-1.7-alt12.