[bug] gitk can not read history if diff color is enabled

Reproduced in git version 1.5.3.4.217.gbfc1, although it's been this way for a while. To see the bug, enable color diff with

[diff] color

and launch gitk on any repository (like the Linux kernel tree). The result is a dialog box "Can't parse git log output '\x1b[33mcommit" etc. qgit can still view the history without errors, so I guess it must be possible to somehow turn off color for a specific query.