__ASSUME_PRIVATE_FUTEX and __ASSUME_FUTEX_CLOCK_REALTIME

[Roland McGrath]

> __ASSUME_PRIVATE_FUTEX and __ASSUME_FUTEX_CLOCK_REALTIME are defined for 
> all supported Linux kernel versions.  Should we say they are a required 
> part of the futex interface for any system, whether or not using the Linux 
> kernel, that may wish to use NPTL, and so remove these macros and all 
> conditionals testing them everywhere in glibc, not just in 
> sysdeps/unix/sysv/linux/ files?

Please, no.  Other systems that provide a futex layer may well provide a
much less fully featureful one than Linux has.