[oe] gtk+-native build problem

[Steffen Sledz]

While running some builds for testing-next i hit a problem with gtk+-native.

The do_configure stage failed with "configure: error: *** Sorry,
cups-config present but cups/cups.h missing." (for details see
<http://tinderbox.openembedded.org/packages/734326/>).

I guess the problem is that at the build host cups is installed but not
cups-devel and gtk+-native somehow likes to use it.

Can someone have a look at it. May be a cups-dev dependency in gtk+.inc
fixes the problem?

Steffen