������ ������ It would be nice to also change signbit definition on systems that
������ ������ doesn't support it, so it at least works for normal numbers.

The signbit() function is actually part of C99, not my implementation,
so I think it should be supported on most systems? Though I am not quite
sure...

It's not available when compiled with Visual Studio. There's following code in math.c:
������ ������ #ifndef signbit
������ ������ #define signbit(x) 0
������ ������ #endif
I think it would be better if it's at least changed to something like:
#define signbit(x) ((x)<0 ? 1 : 0)
It will not work correctly for -NAN or -0 but it will not break the cases where old implementation was working.

Sorry I didn't notice my program in VS was linked to the C++ lib for this signbit() function.

"#define signbit(x) ((x)<0 ? 1 : 0)" ������Looks good to me, I will submit a patch. Thanks for the advice :)