Merging r276236 and r276237:

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r276236 | deadalnix | 2016-07-20 21:25:06 -0700 (Wed, 20 Jul 2016) | 9 lines

Expose AttributeSetNode, use it to provide aggregate getter for attribute in the C API.

Summary: See D19181 for context.

Reviewers: whitequark, Wallbraker, jyknight, echristo, bkramer, void

Subscribers: mehdi_amini

Differential Revision: http://reviews.llvm.org/D21265
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r276237 | deadalnix | 2016-07-20 21:31:38 -0700 (Wed, 20 Jul 2016) | 1 line

Add missing import to fix the build
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llvm-svn: 276663