module request: EINVAL synonyms?

[Sam Steingold]

Sometimes system calls fail not because the operation failed but
because the argument was not appropriate.
E.g., fsync(fd) may fail because fd is a TTY.
Normally errno==EINVAL should indicate that, but on some platforms
other errno's are used.
This results in this code in clisp/src/stream.d:

   #ifdef UNIX_IRIX
    if (!(errno==ENOSYS))
   #endif
   #ifdef UNIX_CYGWIN32 /* for Woe95 and xterm/rxvt, and WoeXP /dev/null */
    if ((errno != EBADF) && (errno != EACCES) && (errno != EBADRQC))
   #endif
   #ifdef UNIX_DARWIN
    if ((errno != EOPNOTSUPP) && (errno != ENOTSUP) && (errno != ENODEV))
   #endif
    if (!(errno==EINVAL))
      { OS_error(); }

i.e., errno==ENOSYS must be ignored on IRIX, EBADF on cygwin, ENODEV on mac os x
and EINVAL on all platforms.

I would love to outsource the maintenance of this nightmare to gnulib.
specifically, I want a module einval which would export
#define IS_EINVAL
to config.h
and IS_EINVAL would be defined to
 (errno==EINVAL)||(errno==ENOSYS))
on Irix,
 (errno==EINVAL)||(errno==EBADF))||(errno==EACCES))||(errno==EBADRQC))
on cygwin &c, and
 (errno==EINVAL)
by default.

thanks!

-- 
Sam Steingold <http://sds.podval.org>