Enable-split-ifs
Enable if splitting for arguments of the given function in FGL rewriting.
This sets the entry for the given function in the fgl-fn-modes
table so that when a call of this function is encountered where one or more of
the arguments' rewritten form is a g-ite (if-then-else) object, then the
FGL interpreter will split the interpretation of that function into cases, as
follows:
(f ... (if a b c) ...)
-->
(if a
(f ... b ...)
(f ... c ...))
See fgl-handling-if-then-elses for more discussion of the handling of
g-ite objects.
