Function pointers and #defines

["Justin Carlson" <justinca@cs.cmu.edu>]

A fair number of places in the headers, we have stuff like this:

void (*_some_fn)(int arg1, int arg2);
#define some_fn(arg1, arg2) _some_fn(arg1, arg2)

Why do we do this, as opposed to:

void (*some_fn)(int arg1, int arg2);

Both syntaxes result in being able to say

some_fn(1, 2);

but the latter is both clearer and shorter.  Is there some deep,
mystical C reason that we use the former, or did someone do it that way
a long time ago and no one has changed it?

-Justin