Re: [PATCH] Document that PF_KTHREAD _is_ ABI

* Alexey Dobriyan:

Some aren't -- PF_FORKNOEXEC. However it is silly for userspace to query it
because programs knows if it forked but didn't exec without external help.

Libraries typically lack that knowledge, and may have reasons to
detect forks.  But there are probably better ways than this flag, like
a MADV_WIPEONFORK mapping, or comparing counters in MAP_PRIVATE and
MAP_SHARED mappings.