IEXTEN bug in ISC 2.2 compiler POSIX support

[Bruce R. Larson]

SUMMARY
We discovered a bug in the ISC 2.2 compiler.  When _POSIX_SOURCE is
defined, IEXTEN is treated as if it was XCASE.

BACKGROUND
When compiling tcsh-5.20* for SysV/386, if POSIX is defined then
termios.h is included otherwise sys/termio.h is included.
The problem seems to be caused by this:
  IEXTEN   in termios.h  (line discipline section) is defined as 0000004
  XCASE  in sys/termio.h (line discipline section) is defined as 0000004

The symptom was that all capital letters were escaped with a backslash.

QUESTION
Is there any other SysV/386 with POSIX compiler support?  And if so,
is there a collision between your defs for IEXTEN and XCASE, or have
you noticed the bug mentioned above?

I doubt this is of general interest, so please respond via email.

Thank you.

Bruce R. Larson
Integral Resources, Milton MA
Internet: ires.com!blarson at cs.umb.edu
Uucp:     ..!cs.umb.edu!ires.com!blarson