Mk/**ruby.mk: Switch from USE_RUBY=yes to USES=ruby
Switch from Mk/bsd.ruby.mk to Mk/Uses/ruby.mk
Notable changes are.
- Mk/bsd.ruby.mk is moved to Mk/Uses/ruby.mk.
- USE_RUBY=yes is replaced with USES=ruby.
- USE_RUBY_EXTCONF is replaced with USES=ruby:extconf.
- USE_RUBY_RDOC is replaced with USES=ruby:rdoc.
- USE_RUBY_SETUP is replaces with USES=ruby:setup.
- RUBY_NO_BUILD_DEPENDS and RUBY_NO_RUN_DEPENDS are replaced with USES=ruby:{build,none,run}.
- RUBY_REQUIRE isn't used anywhere, so removed.
- USES=gem now implies USES=ruby.
This is mainly the work of yasu@ at https://reviews.freebsd.org/D27863
I have just made some cosmetic changes and ran exp-run to test that the
tree is not in a BROKEN state.
Approved by: portmgr
Differential Revision: https://reviews.freebsd.org/D37925