patch for X11R4 version of XDM

[C. Harald Koch]

It turns out that the patches I mentioned previously are very simple; I
forgot that I had figured out an easy preliminary fix.

For those of you who need to get X terminals working under XDMCP, I submit
the following. This enables support for XDMCP at the expense of disabling
support for the Xservers file.

I am working on a proper fix, but it is low on my list of priorities.

Basically, the fix is to call WaitForSomething() instead of WaitForChild()
on sgi machines. Normally, the code there will also process dead children
(necessary for Xservers support) but the code also relies heavily on BSD
signal semantics, and fails on SysV machines.

SIGCHLD is ignored to prevent zombies from building up and filling your
process table; otherwise this is a problem because the children are never
reaped.

Use at your own risk. :-)

----------Cut-Here-----------------------------

*** dm.c.orig	Tue Oct 16 15:39:41 1990
--- dm.c	Wed Oct 24 15:17:11 1990
***************
*** 111,117 ****
      ScanServers ();
      StartDisplays ();
      (void) signal (SIGHUP, RescanNotify);
! #ifndef SYSV
      (void) signal (SIGCHLD, ChildNotify);
  #endif
      while (AnyWellKnownSockets() || AnyDisplaysLeft ())
--- 122,130 ----
      ScanServers ();
      StartDisplays ();
      (void) signal (SIGHUP, RescanNotify);
! #ifdef SYSV
!     (void) signal (SIGCHLD, SIG_IGN);
! #else
      (void) signal (SIGCHLD, ChildNotify);
  #endif
      while (AnyWellKnownSockets() || AnyDisplaysLeft ())
***************
*** 121,127 ****
  	    RescanServers ();
  	    Rescan = 0;
  	}
! #ifdef SYSV
  	WaitForChild ();
  #else
  	WaitForSomething ();
--- 134,140 ----
  	    RescanServers ();
  	    Rescan = 0;
  	}
! #if defined(SYSV) && !defined(sgi)
  	WaitForChild ();
  #else
  	WaitForSomething ();


--
C. Harald Koch  VE3TLA                Alias Research, Inc., Toronto ON Canada
chk%alias at csri.utoronto.ca      chk at gpu.utcs.toronto.edu      chk at chk.mef.org
"Open the Zamboni! We're coming out!" - Kathrin Garland and Anson James, 2299