Files which are recursively included may not be handled correctly

[bright-tools]

Say we have something like this:

Header.h

extern int mex;
# if defined FOO

extern int foo;
# undef FOO
# include "header.h"
# else

extern int moo;
# endif

Where a file effectively includes itself, this may not be handled correctly by CCSM at the moment - CCSM is likely to process the file twice resulting in the metric count being artificially inflated.