If missing, fall back on the C99 isfinite() macro, just like
the existing finitef() fallback.

The finite() function is deprecated in macOS 10.9 and is
removed (from the SDK) since macOS 11.0.
Signed-off-by: Martin Storsjo <martin@martin.st>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>