extmk.rb: include UPDATE_LIBRARIES

* ext/extmk.rb: include UPDATE_LIBRARIES in SUBMAKEOPTS for NMAKE
  which does not include macro definitions given by command line
  in MAKEFLAGS.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48204 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/extmk.rb

@@ -704,6 +704,7 @@ if $configure_only and $command_output
       submakeopts << 'EXTLIBS="$(EXTLIBS)"'
     end
     submakeopts << 'EXTLDFLAGS="$(EXTLDFLAGS)"'
+    submakeopts << 'UPDATE_LIBRARIES="$(UPDATE_LIBRARIES)"'
     mf.macro "SUBMAKEOPTS", submakeopts
     mf.puts
     targets = %w[all install static install-so install-rb clean distclean realclean]