replacearg
void replacearg(arglist *, u_int, char *, ...)
replacearg(&args, 1, "TWO!");
replacearg(&args, 0, "ONE!");
replacearg(&args, 2, "THREE=3!");
replacearg(&args, 1, "two=%d", 2);
replacearg(&args, 0, "%s", program);
replacearg(&args, 0, "%s", ssh_program);
replacearg(&args, 0, "%s", ssh_program);