Set errno in expm1{,f} / log1p{,f}

[Craig Howland via newlib]

On 7/9/19 9:38 AM, Joern Wolfgang Rennecke wrote:
> I find that the gcc test gcc.dg/torture/pr68264.c fails because expm1 / log1p 
> fail to set errno.
> Fixed with the attached patch.
> OK to commit?
It is interesting to note that the Linux log1p man page says "These functions do 
not set errno."Â  This is in conflict with the C standard and POSIX which call 
for the normal errno behavior for it. Perhaps this explains why errno was not 
being set.

(Changes look good to me, but I don't have authority to approve committal.)

Craig