pkg/52496: modular-xorg-server segfaults on i386-8.99.1, -8.0_BETA

[jdbaker%mylinuxisp.com@localhost]

>Number:         52496
>Category:       pkg
>Synopsis:       modular-xorg-server segfaults on i386-8.99.1, -8.0_BETA
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Aug 20 23:25:00 +0000 2017
>Originator:     John D. Baker
>Release:        NetBSD/i386-8.99.1, NetBSD/i386-8.0_BETA, pkgsrc-2017Q2
>Organization:
>Environment:
NetBSD verthandi 8.99.1 NetBSD 8.99.1 (VERTHANDI) #5: Fri Aug 18 12:12:32 CDT 2017  sysop%x3650.technoskunk.fur@localhost:/r1/build/current/obj/i386/sys/arch/i386/compile/VERTHANDI i386

>Description:
Once the following change:

  http://mail-index.netbsd.org/pkgsrc-changes/2017/08/20/msg161829.html

has been implemented and "graphics/MesaLib" rebuilt, the 'Xorg' server
fails with a segmentation fault.  Rebuilding with the "debug" option
and running under 'gdb' produces the following:

[...]
input-thread: registered device 9
client(0): Reserved pid(15928).
client(0): Reserved cmdname(/usr/pkg/bin/Xorg) and cmdargs(-retro).
input-thread: creating thread
[New LWP 2]

Thread 1 received signal SIGSEGV, Segmentation fault.
0x00000004 in ?? ()
(gdb) bt
#0  0x00000004 in ?? ()
#1  0x08192b7e in DRIBlockHandler (blockData=0x0, pTimeout=0xbfb9fbb8)
    at dri.c:1673
#2  0x08077e8c in BlockHandler (pTimeout=pTimeout@entry=0xbfb9fbb8)
    at dixutils.c:388
#3  0x081c5118 in WaitForSomething (are_ready=<optimized out>) at WaitFor.c:219
#4  0x0807300c in Dispatch () at dispatch.c:422
#5  0x0807752f in dix_main (argc=argc@entry=2, argv=argv@entry=0xbfb9fcdc, 
    envp=envp@entry=0xbfb9fce8) at main.c:287
#6  0x081de9ea in main (argc=2, argv=0xbfb9fcdc, envp=0xbfb9fce8)
    at stubmain.c:34

The 'gdb' session hangs on exit and must be kill()ed with "-9".

In case it matters, the machine on which this test is run has an
ATI Rage 128 video card and the kernel is built without any DRMKMS
drivers and with the UMS "r128drm" driver included.
>How-To-Repeat:
Starting with pkgsrc-2017Q2, update "graphics/MesaLib" to HEAD and
replace.

Attempt to start modular Xorg ('X' or 'Xorg').

>Fix: