[CM] Trouble buillding cm on Arch Linux

[Bill Schottstaedt]

It looks like a version mismatch -- I added the s7_scheme* pointer
to s7_number_to_real about a month ago, but I think cm is older
than that.  The previous version was:

s7_Double s7_number_to_real(s7_pointer x)
{
  switch (type(x))
    {
    case T_INTEGER: return((s7_Double)integer(x));
    case T_RATIO:   return((s7_Double)numerator(x) / (s7_Double)denominator(x));
    case T_REAL:    return(real(x));
    case T_COMPLEX: return(real_part(x));
    }
  return(0.0); 
}

but I needed the s7_scheme* pointer for error handling and so on.
I thought I looked for s7_number_to_real in the cm sources before
changing it!  Perhaps you can get cm to compile if you use the 
version above.