Make it so that we actually generate definitions for explicitly
defaulted default constructors.

As it happens, making sure that we handle out-of-line defaulted
functions properly will involved making sure that we actually parse them
correctly, so that's coming after.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131224 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed