* sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h: #include <nldbl-abi.h>
to define LONG_DOUBLE_COMPAT_VERSION. Use that in place of
NLDBL_VERSION.
* sysdeps/ieee754/ldbl-opt/Versions: Include <nldbl-abi.h>.
* sysdeps/unix/sysv/linux/sparc/sparc32/Versions: Revert last change.