Ruby

common.mk: revert to MINIRUBY

• common.mk: revert using BOOTSTRAPRUBY for enc.mk, as
  enc/depend uses CONFIG. [ruby-core:68647] [Bug #11004]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50099 b2dd03c8-39d4-4d8f-98ff-823fe69b080e