cat_prefix_varname(int prefix, char_u *name)
{
    int		len;

    len = (int)STRLEN(name) + 3;
    if (len > varnamebuflen)
    {
	vim_free(varnamebuf);
	len += 10;			// some additional space
	varnamebuf = alloc(len);
	if (varnamebuf == NULL)
	{
	    varnamebuflen = 0;
	    return NULL;
	}
	varnamebuflen = len;
    }
    *varnamebuf = prefix;
    varnamebuf[1] = ':';
    STRCPY(varnamebuf + 2, name);
    return varnamebuf;
}
cat_prefix_varname(int prefix, char_u *name)
{
    int		len;

    len = (int)STRLEN(name) + 3;
    if (len > varnamebuflen)
    {
	vim_free(varnamebuf);
	len += 10;			 
	varnamebuf = alloc(len);
	if (varnamebuf == NULL)
	{
	    varnamebuflen = 0;
	    return NULL;
	}
	varnamebuflen = len;
    }
    *varnamebuf = prefix;
    varnamebuf[1] = ':';
    STRCPY(varnamebuf + 2, name);
    return varnamebuf;
}