Merge the GCC5 and build fix branches. This fixes all warnings produced by GCC 5, except the ones related to system functions. Those could be fixed by including the proper headers, but it would be better to replace the system-dependent code with functions from mdport.c.

[Desktop Entry]
Encoding=UTF-8
Name=Rogue
GenericName=Rogue
Comment=The original curses-based adventure game
Exec=rogue
Icon=rogue.png
Terminal=true
Type=Application
Categories=Game;RolePlaying;
Version=1.0