Building Speedb fails with Clang 14

[isaac-io]

Building Speedb on my machine using Clang 14 fails with the following errors:

/home/isaac/projects/speedb-io/options/db_options.h:120:21: error: definition of implicit copy constructor for 'MutableDBOptions' is deprecated because it has a user-declared copy assignment operator [-Werror,-Wdeprecated-copy]
  MutableDBOptions& operator=(const MutableDBOptions&) = default;
                    ^
/home/isaac/projects/speedb-io/db/compaction/compaction_job.cc:439:7: note: in implicit copy constructor for 'rocksdb::MutableDBOptions' first required here
      mutable_db_options_copy_(mutable_db_options),
      ^

To Reproduce

mkdir build
CC=clang CXX=clang++ cmake .. -GNinja
ninja

Expected behavior

The build completes successfully.

Environment (please complete the following information):

• OS (e.g. output of uname -omsr and distribution name and version): Arch Linux with Linux 5.18.10-arch1-1 x86_64 GNU/Linux
• Compiler (e.g. output of gcc --version):

clang version 14.0.6
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

[isaac-io]

Turns out this was caused by a change that I introduced in #7. Simply reverting it fixes the problem.