Fix bug of clearing COF_TEMP_MARK. draw_shapes_in_dirty_areas() mark COF_TEMP_MARK on coords and clear them before leaving. But, it always clear the same one coord for several times and keep others untouched. It is a logical error. It can be avoided by avoiding to use the variable at mutliple place for different purpose in a function, and compiler will check it out by yelling that the variable is used before assigning a value.

divert([-1])

define([_arg1], [$1])

define([_foreach], [ifelse([$2], [()], [],
[define([$1], _arg1$2)$3[]_foreach([$1], (shift$2), [$3])])])

define([foreach], [pushdef([$1])_foreach($@)popdef([$1])])

divert[]dnl