Else
----
The `#else' directive can be added to a conditional to provide
alternative text to be used if the condition fails. This is what it
looks like:
#if EXPRESSION
TEXT-IF-TRUE
#else /* Not EXPRESSION */
TEXT-IF-FALSE
#endif /* Not EXPRESSION */
If EXPRESSION is nonzero, the TEXT-IF-TRUE is included and the
TEXT-IF-FALSE is skipped. If EXPRESSION is zero, the opposite happens.
You can use `#else' with `#ifdef' and `#ifndef', too.