* configure.in (ARFLAGS): check if deterministic mode flag is
	  effective, which is on by default on Ubuntu.


	configure.in: use libtool

	* configure.in: use libtool on macOS to suppress a warning against
	  debug_counter.o, which has no symbols unless USE_DEBUG_COUNTER
	  is set to non-zero.

	configure.in: use newer libtool only

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@62809 b2dd03c8-39d4-4d8f-98ff-823fe69b080e