Workaround egcs-20000131 c++ compiler bug

[Zack Weinberg]

> +#if defined (__GNUC__) && defined (__cplusplus)
> +  alloca (4);
> +#endif

The effect of that is simply to shut off the RTL inliner for that
function.  Is it marked 'inline', and if not, could you add that to
the declaration and see if the problem comes back?  (The tree inliner,
which only exists in C++, will inline functions that use alloca, but
not functions that were not explicitly declared as inline.)

zw