merge revision(s) 43077,43078: [Backport #8937]

	* test/dl/test_base.rb: {libc, libm} detection now handle GNU/Hurd
	  correctly. Patch by Gabriele Giacone (1o5g4r8o@gmail.com).

	* test/fiddle/helper.rb: ditto.
	  [Bug #8937][ruby-core:57311]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@43225 b2dd03c8-39d4-4d8f-98ff-823fe69b080e