Fix handling of statements that are not in a case.
Fix handling of statements that are not in a case.

Such statements (typically #lines) were output *after*
the case it was preceding.  This screwed #lines.

	* build-aux/fuse-switch ($pre_case): New.
	Use it.

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport