__fpclassifyd problem

[David Schultz]

I'm just catching up on -CURRENT, but I wanted to point out that
this was fixed last night in:

	src/lib/msun/src/e_scalbf.c,v1.8
	src/lib/msun/src/e_scalb.c,v1.10

The fix was to use the old versions of isnan() and isinf()
specifically in the two places in libm where they are needed.
This problem illustrates that we need to be careful as we roll
forward support for C99 features that cannot be implemented as
regular functions, but that are regular functions in C89.  I
expect that once all that support is in the tree, we can do a
single libm version number bump and remove the compatibility hacks.