sci-libs/libsc: Drop old; version bump; update metadata.xml

Package-Manager: portage-2.2.8-r2
sci-libs/p4est: Version bump; update metadata.xml

Package-Manager: portage-2.2.8-r2
sci-libs/p4est: Fix build dependencies

Package-Manager: portage-2.2.8-r2
Merge pull request #278 from tamiko/bump_p4est

Bump sci-libs/libsc and sci-libs/p4est