vendor: Update ruby-macho to 0.2.6.

[woodruffw]

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This brings fixes for behavior expected in #1460.

cc @MikeMcQuaid, @UniqMartin

[MikeMcQuaid]

As #1460 was reverted could you add its changes to this PR too? Thanks!

[MikeMcQuaid]

Thanks again @woodruffw!

[fxcoudert]

lcs.map(&:name).map(&:to_s) should be lcs.map(&:name).map(&:to_s).uniq otherwise universal libraries show up twice. This then triggers a failure to bottle universal binaries & libraries, like my wine PR (Homebrew/homebrew-core#10532 ; test results: https://bot.brew.sh/job/Homebrew%20Core/17442/version=sierra/testReport/junit/brew-test-bot/sierra/bottle_wine/)

Before the commit, this code relied on macho.linked_dylibs, which does apply uniq:

    def linked_dylibs
      # Individual architectures in a fat binary can link to different subsets
      # of libraries, but at this point we want to have the full picture, i.e.
      # the union of all libraries used by all architectures.
      machos.map(&:linked_dylibs).flatten.uniq
    end