There was an ECL port attempt but I didn't track it too closely lately I remember vaguely that a few scheme would be available and I thing CCL is also in the picture. I'd rather talk for MKCL if you don't mind.
not at all, especially if i understand correctly ECL is unmaintained and MKCL is an alive fork.
is mkcl viable to run as a native app both on iOS and android?
right now it is not, period. But it is on my list of things to do any month now. As soon as I get the ffi to be C99-complete as I say, and that I am done with the proper interface to the "environment" (that CLTL2 thing, you know) I will get right to it.
porting to android sounds like a fun project. see you on mkcl-devel... :)
FTR, there's this commercial lisp:
and this thread with some comments of interest:
http://www.reddit.com/r/lisp/comments/1lemlk/best_lisp_repl_for_android_tabl...
and then there's probably the most viable:
especially this project based on gambit. after a very cursory search, this seems to be the most inviting/interesting without actually trying it:
i personally won't touch any non-opensource solution when i'm venturing into such uncharted territory. in that case being able to fix stuff myself is priority for me.