* Ruby.mk (SRCS): move headers last for TAGS.
* Ruby.mk (reconfig): target to re-configure.
* Ruby.mk (.do-up): remove intermediate files to commit.
* ruby.rb: parentheses to suppress a warning.
* ruby.rb: remove stale --debug option.
* Ruby-toplevel.mk: add + flag for jobserver.
* Ruby-toplevel.mk (versions): search Makefile instead of GNUmakefile.