[BZ4997]
* sysdeps/powerpc/powerpc32/fpu/s_lround.S (__lround): Fixed erroneous
result when x is +/-nextafter(+/-0.5,-/+1) i.e. all 1's in the
mantissa.
* sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround):
Likewise. Also account for when x is an odd number between 2^52
and 2^53-1.
* sysdeps/powerpc/powerpc64/fpu/s_llround.S (__llround): Likewise.
* sysdeps/powerpc/powerpc64/fpu/s_llroundf.S (__llroundf): Likewise.
* math/libm-test.inc (lround_test, llround_test): Added test cases to
detect aforementioned erroneous conditions.