I've just downloaded the source for OpenLB and there's a Makefile in that directory. So, just type "make" to build the executable. Also, for what it's worth, using -c wouldn't build the complete exectuable; it would only generate object files and you'd need to perform the linking step manually.
Edit: There is also a user's guide on the OpenLB website, so reading that would probably have told you how to build the examples.
Last edited by Nylex; 08-26-2011 at 02:09 AM.