MFH: r370066

- Update slib and slib-guile to 3b4
- Fix build for lang/slib with new texinfo [1]
- Convert slib-guile @exec/@unexec directives to post install/deinstall scripts
- Add new port slib-guile2 based on slib-guile
- Remove dirrms

Approved by:	ports-secteam (rea)