errno question

[Guy Harris]

>Oh *PEST*.  I just noticed that on one of our V.3 systems the two
>names are bound to different numbers, but on another they are bound
>to the same number and both glossed as {Deadlock condition}.  SunOS
>4.0 has only EDEADLK, glossed as {Deadlock condition}.  So it looks
>as though EDEADLK is a V.3 thing, and EDEADLOCK is more recent than
>that.  Presumably "some obscure POSIX-related stuff"...

SunOS's use probably dates back to 3.2, which picked up the locking code
from S5R2.  I don't have S5R2 source handy, so I don't know whether
EDEADLOCK existed in S5R2 or not; in the S5R3.1 source from AT&T,
they have different values.

Nevertheless, the S5R3.1 code still uses EDEADLK to report file-locking
deadlocks, not EDEADLOCK (the reference to "obscure POSIX-related stuff"
was made because I don't have 1003.1 handy and don't know what POSIX
specifies as the deadlock return code - if it even specifies it at all).