COMPAT_43

[Divacky Roman]

hi,

the only use of COMPAT_43 (beside running 43 programs) is linux emulation layer
and some tty-related stuff. but GENERIC etc. still shouts KEEP THIS on this
option. is this necessary? 

forcing COMPAT_43 pesimises performnce (additional locking in some places etc.)
and most users dont need it (for linux emulation I am working on a patch and
also the tty part is being worked on). could the [KEEP THIS!] text be changed
to something more reflecting reality? like keep this for linuxator/tty or
something like that

thnx

roman