[C++11] Use 'nullptr'.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@210447 91177308-0d34-0410-b5e6-96231b3b80d8
Simplify code. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@210508 91177308-0d34-0410-b5e6-96231b3b80d8
Prospective build fix following clang r210518

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@210521 91177308-0d34-0410-b5e6-96231b3b80d8
Merge pull request #9 from llvm-mirror/master

git pull