Merge git://git.kernel.org/pub/scm/gitk/gitk

* git://git.kernel.org/pub/scm/gitk/gitk:
  gitk: Fix "can't unset prevlines(...)" Tcl error
  gitk: Avoid an error when cherry-picking if HEAD has moved on
  gitk: Check that we are running on at least Tcl/Tk 8.4
  gitk: Do not pick up file names of "copy from" lines
  gitk: Add support for OS X mouse wheel
  gitk: disable colours when calling git log