The nearbyintl assembly implementation
(sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S)
returns wrong results for some inputs where first double is a exact
integer and the precision is determined by second long double.
Checking on implementation comments and history, I am very confident the
assembly implementation was based on a version before commit
5c68d401698a58cf7da150d9cce769fa6679ba5f that fixes BZ#2423 (Errors in
long double (ldbl-128ibm) rounding functions in glibc-2.4).
By just removing the implementation and make the build select
sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c instead fixes the failing
math.
Fixes BZ#16706.
98fb27a373