libc6 and X11 seem not to work together

["Hans-J. Ullrich" <hans.ullrich@loop.de>]

Dear maintainers, 

since the last upgrade (debian-amd64/sid) it is not more possible to start X. 
It seems, libc6 is incompatible to the xserver-packages in debiansid

Backtrace:
0: /usr/bin/X11/X(xorg_backtrace+0x26) [0x4edfe6]
1: /usr/bin/X11/X(xf86SigHandler+0x39) [0x483699]
2: /lib/libc.so.6 [0x7f7e17a41db0]               
3: /usr/bin/X11/X(DGAAvailable+0x39) [0x4823c9]  
4: /usr/bin/X11/X(xf86DiDGAInit+0x30) [0x4ae200] 
5: /usr/bin/X11/X(xf86CrtcScreenInit+0x10d) [0x4aafad]
6: /usr/lib/xorg/modules/drivers//radeon_drv.so [0x7f7e15e26a49]
7: /usr/bin/X11/X(AddScreen+0x1c6) [0x432ac6]                   
8: /usr/bin/X11/X(InitOutput+0x241) [0x46d361]                  
9: /usr/bin/X11/X(main+0x200) [0x4331d0]                        
10: /lib/libc.so.6(__libc_start_main+0xe6) [0x7f7e17a2e5c6]     
11: /usr/bin/X11/X [0x432819]         


For me it looks like Xorg gets a problem with the latest libc6-version from 
sid. Can someone confirm this ? 

Another info: It might not appear on every computer. Mine is working fine 
(amd64 + Nvidia-driver), but the one from a friend (amd64 + ati-driver) causes 
the message above.

Should I file a bugreport?

Greets

Hans