common.mk: update unicode data only if BASERUBY is available
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48278 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
common.mk: update unicode data only if BASERUBY is available
BASERUBY is available. MINIRUBY cannot load extension libraries,
so cannot update Unicode data.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48278 b2dd03c8-39d4-4d8f-98ff-823fe69b080e