CMake cannot find Qt4

[Davide Liessi]

Hi all.
I'm trying to build a project that requires Qt4 and uses CMake.
When I run cmake I get the following error:

CMake Error at /opt/local/share/cmake-3.3/Modules/FindQt4.cmake:1324 (message):
  Found unsuitable Qt version "" from NOTFOUND, this code requires Qt 4.x

Any hint on how to solve this?

The versions of the ports are:
$ port installed cmake qt4-mac
The following ports are currently installed:
  cmake @3.3.2_1 (active)
  qt4-mac @4.8.7_2 (active)

Best wishes.
Davide