Merge branch 'master' into core-updates

gnu: clucene: Add patch to indicate linking with clucene-shared, not only
   clucene-core, to pkgconfig.

* gnu/packages/patches/clucene-pkgconfig.patch: New file.
* gnu-system.am (dist_patch_DATA): Register patch.
* gnu/packages/rdf.scm (clucene): Use patch.