Remove reference from common_type definition.  It looks like a recent clang decltype implementation got fixed/improved and exposed this.  Fixes http://llvm.org/bugs/show_bug.cgi?id=12007.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@150581 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed