PATCH: atan2 +0/-0 special case wrapper fixes

[Cary R.]

The wrapper code for atan2 returns 0.0 and raises a domain error if both
arguments to atan2 are zero (ignoring the sign). Recent versions of glibc
return the result specified in the base atan2 functionality and explicitly
state that this (atan2(0,0), etc.) does not raise a domain error. This
patch removes all the special case code in the wrapper files since it is
not needed to get the same result as glibc. The documentation is also
updated to be consistent with these changes.

Here's something for the Changelog.

* libm/math/w_atan2.c: Fix atan2 to be consistent with glibc
(atan2(+0,-0), atan2(-0,-0) and atan(-0,+0))
* libm/math/wf_atan2.c: Ditto.

The patch and a test program are attached.

Cary


 
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