Basically done the chibi impl, there are 6 test failures which appear to be in my own code.
Note the test suite refers to `fx=?' etc. instead of `fx='
The implementation of at least fxlogical-shift-right appears to be missing.
Regarding the cond-expand code for chibi, you probably want(include-shared "srfi/142/bit"), not (include-shared "bit"). Alsothe libraries should be named (srfi 143), not (srfi-143).
Otherwise, if there's also a Gauche impl I think there's no need to wait on chibi.