Merge branch 'jn/mediawiki-makefile-updates'

Build and installation procedure clean-up. * jn/mediawiki-makefile-updates: git-remote-mediawiki build: handle DESTDIR/INSTLIBDIR with whitespace git-remote-mediawiki build: make 'install' command configurable git-remote-mediawiki: honor DESTDIR in "make install" git-remote-mediawiki: do not remove installed files in "clean" target