Hoary: unmet build dependencies when trying to build hostap

[Ubu Roi]

I downloaded the hostap-source package (apt-get source).
When trying to build the deb package using dpkg-buildpackage
I get the following:
 dpkg-checkbuilddeps: Unmet build dependencies: cdbs
 dpkg-buildpackage: Build dependencies/conflicts unsatisfied; aborting.
 dpkg-buildpackage: (Use -d flag to override.)

How can I find out which dependencies/conflicts are unsatisfied?

Ubu