The source distribution of ChessDB, for example the lastest release ChessDB-3.6.15.tar.gz, includes software from other projects. I understand that this software should not be distributed under ChessDB if it hasn't have been modified by the project. The README or INSTALL should include information about which software is necesary to install chessdb and which software is recommended to play chessdb.
Some of this software is that i found is:
* src/zlib (it's necesary that the user has zlib to compile chessdb but this is a requirement to check by the configure process)
By other side, there is a lack of information about the copyright and license of some parts of ChessDB: bitmaps, bitmaps2, sounds, ...
In my opinion these issues are important to simplify the build process, minimize the size of the tar.gz file and to avoid legal issues.