MSVC6 compatibility

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9494 387891d4-d844-0410-90c0-e4c51a9137d3
add files to project

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9495 387891d4-d844-0410-90c0-e4c51a9137d3