I looked into how that library is actually used later on, and it turns
out it's in only one function in private/chibi-sxml.scm, and that only
a use of the let-optionals macro that would have worked with the more
limited version that comes in Chicken's core library. Oh well. It was
educational, at least.
Right. If that's the only place, my vote is to patch our copy of
chibi-sxml not to require the SRFI.
The downside is that each upstream release of chibi-sxml will have to be
patched, but that library is quite stable and probably won't get many
essential upgrades.
I suggested to Alex (who wrote chibi-sxml) to manually unroll the
optional arguments parsing for that library and he said it's fine. The
patch has now been mainlined:
https://github.com/ashinn/chibi-scheme/commit/561fc1bae083f98e02a5e696c5be13c9f4d0c4bd
If we upgrade the copy in the srfi-tools source tree, that solves the
immediate problem.
