I added some hacks to Install_Build_Needed_Packages to get libmysqlclient15-dev installed.
just get the sources at svn.charonmedia.org and type:
Alternatively, you can inspect src/Ubuntu_Helpers/BuildUbuntu_Functions.sh and look at the Install_Build_Needed_Packages function. The hack I made may not be the best hack. It might be better to force a specific libmysqlclient15-dev package, rather than specific libmysqlclient15off and mysql-common packages. For an example, see libvorbis-dev, where I forced a specific libvorbis-dev version rather than upgrading the underlying library.