Looking at ugen.c and the man page, I saw that the -current ugen driver
supports isochronous endpoints (doesn't it ?).

I am using 1.5, and I don't want to switch to -current right now.

I was wondering if simply copying the ugen.c of the -current tree to my
1.5 tree was sufficient to be  able to use isochronous endpoints for the
ugen driver ? Are there any other files I should update ?

If getting isochronous mode is that easy, maybe would it be of interrest
to pull up the -current ugen revision to the 1.5 tree ?