[CM] S7 C function arguments corrupted in loop

[bil at ccrma.Stanford.EDU]

Thanks very much for the bug report!  That was a tricky one -- I managed
to overoptimize op_x_aa, using a constant list where it got stepped on.
A quick fix, around line 90626, change

   sc->value = c_function_call(f)(sc, with_list_t2(fx_call(sc, 
cdr(code)), fx_call(sc, cddr(code))));

to

   sc->value = c_function_call(f)(sc, list_2(sc, fx_call(sc, cdr(code)), 
fx_call(sc, cddr(code))));

I need to figure out what the "right thing" is here.

By the way, it had never occurred to me to use c-define in the midst of 
an expression like that --
kinda neat!  I think I'll include something like that in the docs.

Thanks again.