A change during the 1.20 development cycle resulted in fbconfigs being walked
and deallocated individually during __glXScreenDestroy.  This change
now avoids a use-after-free caused by that change.

==50859==ERROR: AddressSanitizer: heap-use-after-free on address 0x00010d3819c8 at pc 0x0001009d4230 bp 0x00016feca7a0 sp 0x00016feca798
READ of size 8 at 0x00010d3819c8 thread T5
    #0 0x1009d422c in __glXScreenDestroy glxscreens.c:448
    #1 0x10091cc98 in __glXAquaScreenDestroy indirect.c:510
    #2 0x1009d2734 in glxCloseScreen glxscreens.c:169
    #3 0x100740a24 in dix_main main.c:325
    #4 0x10023ed50 in server_thread quartzStartup.c:65
    #5 0x199ae7fd0 in _pthread_start+0x13c (libsystem_pthread.dylib:arm64e+0x6fd0)
    #6 0x199ae2d38 in thread_start+0x4 (libsystem_pthread.dylib:arm64e+0x1d38)

0x00010d3819c8 is located 200 bytes inside of 12800-byte region [0x00010d381900,0x00010d384b00)
freed by thread T5 here:
    #0 0x101477ba8 in wrap_free+0x98 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x3fba8)
    #1 0x1009d4240 in __glXScreenDestroy glxscreens.c:449
    #2 0x10091cc98 in __glXAquaScreenDestroy indirect.c:510
    #3 0x1009d2734 in glxCloseScreen glxscreens.c:169
    #4 0x100740a24 in dix_main main.c:325
    #5 0x10023ed50 in server_thread quartzStartup.c:65
    #6 0x199ae7fd0 in _pthread_start+0x13c (libsystem_pthread.dylib:arm64e+0x6fd0)
    #7 0x199ae2d38 in thread_start+0x4 (libsystem_pthread.dylib:arm64e+0x1d38)

previously allocated by thread T5 here:
    #0 0x101477e38 in wrap_calloc+0x9c (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x3fe38)
    #1 0x100925a40 in __glXAquaCreateVisualConfigs visualConfigs.c:116
    #2 0x10091cb24 in __glXAquaScreenProbe+0x224 (X11.bin:arm64+0x100730b24)
    #3 0x1009cd840 in xorgGlxServerInit glxext.c:528
    #4 0x10074539c in _CallCallbacks dixutils.c:743
    #5 0x100932a70 in CallCallbacks callback.h:83
    #6 0x100932478 in GlxExtensionInit vndext.c:244
    #7 0x10020a364 in InitExtensions miinitext.c:267
    #8 0x10073fe7c in dix_main main.c:197
    #9 0x10023ed50 in server_thread quartzStartup.c:65
    #10 0x199ae7fd0 in _pthread_start+0x13c (libsystem_pthread.dylib:arm64e+0x6fd0)
    #11 0x199ae2d38 in thread_start+0x4 (libsystem_pthread.dylib:arm64e+0x1d38)

Regressed-in: 4b0a3cba


CC: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
(cherry picked from commit 487286d4)