Why do we need to fixinclude HUGE_VAL definitions in math.h?

[Nathanael Nerode]

fixincludes likes to replace (in math.h)
#define HUGE_VAL blah

with
#ifndef HUGE_VAL
#define HUGE_VAL blah
#endif

I can't figure out *why*, though.  Who's defining HUGE_VAL before math.h
and wants to keep it from being trashed?

(I don't quite know what HUGE_VAL is used for anyway.)

(This is another one of the tests which I'm trying to straighten out for
OpenBSD fixincludes normalization, because it triggers on OpenBSD, but
isn't changed with the current unusual fixincludes script.)

-- 
Nathanael Nerode  <neroden at gcc.gnu.org>
http://home.twcny.rr.com/nerode/neroden/fdl.html