emerge: there are no ebuilds built with USE flags to satisfy

Discussions & Opinions
1

hell,
when udpdate encounter this problem:

   emerge -auND world

These are the packages that would be merged, in order:

Calculating dependencies... done!

emerge: there are no ebuilds built with USE flags to satisfy "media-libs/raptor:2[xml]".
!!! One of the following packages is required to complete your request:
- media-libs/raptor-2.0.7::gentoo (Missing IUSE: xml)
- media-libs/raptor-2.0.7::gentoo (Missing IUSE: xml)
(dependency required by "dev-libs/redland-1.0.15" [binary])
(dependency required by "app-office/libreoffice-3.5.2.2" [installed])
(dependency required by "@selected" [set])
(dependency required by "@world" [argument])
2

hello,solve my problem.remove software by dependency and use this command:
emerge --verbose -ac
this command also see which package and dependency package must be remove. if want just remove that package and not working dependency use this command:
emerge --unmerge
recommend this problem must be remove package and dependency.