[CLAM] Compilation in debug or release mode

[Maarten de Boer]

By default, CLAM is compiled in debug more. This results in a much
larger and slower executable. If you do not plan to run CLAM application
in a debugger, make sure you run ./configure with the following flags:

$ cd unix_tools
$ ./configure --disable-debug-checks --disable-debug

You will have to recompile your application so these changes take effect
(make clean; make depend; make)

Maarten