Add methods to merge an AttrBuilder into another builder.

This is useful when parsing an object that references multiple attribute groups.

N.B. If both builders have alignments specified, then they should match!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174480 91177308-0d34-0410-b5e6-96231b3b80d8
Add a 'StringRef' version of hasAttribute.

Fix the 'operator==' and 'hasAttributes' queries to take into account
target-dependent attributes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174481 91177308-0d34-0410-b5e6-96231b3b80d8