Summary:
GCC 9 added -Wdeprecated-copy (as part of -Wextra). This diagnostic is already implemented in Clang too, just hidden under -Wdeprecated (not on by default).
This patch adds -Wdeprecated-copy and makes it compatible with GCC 9+.
This diagnostic is heavily tested in deprecated.cpp, so I added simple tests just to check we warn when new flag/-Wextra is enabled.
Reviewers: rsmith, dblaikie
Reviewed By: dblaikie
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D70342