Merge branch 'ab/build-gitweb'

Teach "make all" to build gitweb as well. * ab/build-gitweb: gitweb/Makefile: add a "NO_GITWEB" parameter Makefile: build 'gitweb' in the default target gitweb/Makefile: include in top-level Makefile gitweb: remove "test" and "test-installed" targets gitweb/Makefile: prepare to merge into top-level Makefile gitweb/Makefile: clear up and de-duplicate the gitweb.{css,js} vars gitweb/Makefile: add a $(GITWEB_ALL) variable gitweb/Makefile: define all .PHONY prerequisites inline