file names

Hi, I was was looking into the file names and noticed that they are
not consistent.

Some files are named like:

foo-bar.[c/h]

Others are:

foo_bar.[c/h]

On top of the git directory:

# With dash
$ lc *.c | grep - | wc -l
72

$ lc *.h | grep - | wc -l
25

# With underline
$ ls *.c | grep _ | wc -l
5

$ ls *.h | grep _ | wc -l
1

So it seems from this data, there is a preference for naming files
using dash over underline.

So the question is, should the files using underline be converted to
use dash instead? And should this be documented somewhere? Maybe in
CodingGuidelines?

Thanks in advance.