*/*: adapt to new guile framework

 - change all ports using guile to USES=guile
 - flavorize guile-lib, guile-cairo, slib-guile

PR:		260960
Reported by:	Martin Neubauer <m.ne@gmx.net>
Approved by:	bofh
Differential Revision:	https://reviews.freebsd.org/D40194