not compatible with mac 10.15


I try to build from souce

- cmake pass
- make pass
- cpack pass

```
[100%] Built target fdbbackup
Scanning dependencies of target actor_flamegraph
[100%] Building CXX object contrib/monitoring/CMakeFiles/actor_flamegraph.dir/actor_flamegraph.cpp.o
[100%] Linking CXX executable ../../bin/actor_flamegraph
[100%] Built target actor_flamegraph
yutiansut@yutiandeMacBook-Pro build % cpack
CPack: Create package using TGZ
CPack: Install projects
CPack: - Run preinstall target for: foundationdb
CPack: - Install project: foundationdb []
CPack: - Install component: clients-tgz
CPack: - Install component: server-tgz
CPack: Create package
CPack: - package: /Users/yutiansut/development/foundationdb/build/packages/foundationdb-clients_7.0.0-0.45e24fc6a1794e3f3f9ca909e872d51633115b32.PRERELEASE.x86_64.tar.gz generated.
CPack: - checksum file: /Users/yutiansut/development/foundationdb/build/packages/foundationdb-clients_7.0.0-0.45e24fc6a1794e3f3f9ca909e872d51633115b32.PRERELEASE.x86_64.tar.gz.sha256 generated.
CPack: - package: /Users/yutiansut/development/foundationdb/build/packages/foundationdb-server_7.0.0-0.45e24fc6a1794e3f3f9ca909e872d51633115b32.PRERELEASE.x86_64.tar.gz generated.
CPack: - checksum file: /Users/yutiansut/development/foundationdb/build/packages/foundationdb-server_7.0.0-0.45e24fc6a1794e3f3f9ca909e872d51633115b32.PRERELEASE.x86_64.tar.gz.sha256 generated.
CPack: Create package using productbuild
CPack: Install projects
CPack: - Run preinstall target for: foundationdb
CPack: - Install project: foundationdb []
CPack: - Install component: clients-pm
CPack: - Install component: server-pm
CPack: Create package
CPack: - Building component package: /Users/yutiansut/development/foundationdb/build/_CPack_Packages/Darwin/productbuild/FoundationDB-7.0.0/Contents/Packages/FoundationDB-7.0.0-clients-pm.pkg
CPack: - Building component package: /Users/yutiansut/development/foundationdb/build/_CPack_Packages/Darwin/productbuild/FoundationDB-7.0.0/Contents/Packages/FoundationDB-7.0.0-server-pm.pkg
CPack: - package: /Users/yutiansut/development/foundationdb/build/packages/FoundationDB-7.0.0.pkg generated.
CPack: - checksum file: /Users/yutiansut/development/foundationdb/build/packages/FoundationDB-7.0.0.pkg.sha256 generated.
```

but when i got the pkg installed , found a compatible problem