I've completed the addition of a "golden" version of FLTK to our source
tree. Appending a patch to extensions.patch isn't as straightforward as
it might sound, and I'm sick of maintaining that file. It's easier to
just put our blessed version in the source and build it along with
everything else.
ossman (irc) was so kind providing this patch:
http://mawercer.de/~marc/tmp.patch
Applying it in addition to the patch shipping with trunk (-r 4600) makes
current fltk [1] compile.
It fixes errors such as "missing fl_cursor_wait.xpm file not found"
So I recommend appending it to fltk/extensions.