[xdebug-general] Configure: error: C++ preprocessor "/lib/cpp" fails sanity check

Good day,

I've a very strange problem. I'm trying to install xdebug-2.0.0beta1 on
a fresh debian installation. The configure command (./configure
--enable-xdebug) stops with the following message:

checking for g++... no
checking for c++... no
checking for gpp... gpp
checking whether we are using the GNU C++ compiler... no
checking whether gpp accepts -g... no
checking how to run the C++ preprocessor... /lib/cpp
configure: error: C++ preprocessor "/lib/cpp" fails sanity check
See `config.log' for more details.

Google tells me that my gcc compiler is not installed or broken. But I
just compiled and installed PHP, Apache, MySQL and some other
programs.. The config.log doesn't give much useful info btw.

Might be a bit of a newbie question, but google doesn't help me right now..

Thanks,
Bert