This patch was created against gtkextra-2 (cvs of 18th
It replaces the use of two private gtk functions
_gtk_draw_insertion_cursor) with exact copies of those
functions renamed to _gtkextra_*.
This is useful as a quick hack to get gtkextra to
compile under mingw, but it should not be used long
term since it assumes details of the internal gtk setup
which could quite easily change even in a minor
release. The copied code comes from gtk 2.0.3.