meas_feed fails to compile if libcdk5-dev is not installed

Hi Harald,

OpenBSC fails to compile because meas_feed unconditionally depends on cdk.h. If this file is not available, configure just issues

checking cdk/cdk.h usability... no checking cdk/cdk.h presence... no checking for cdk/cdk.h... no

but does not fail. On the other hand, the meas_tool's Makefile does not check for the result of that check before starting the compilation.

So IMO either the configure script should abort (and the package added to debian/control) or the compilation of meas_feed should be optional.

Jacob