This removes font.h dependency from header files such as ags.h and
nact.h. After this, font.h must be explicitly included in order to use
font functions.
We only support a fixed set of modules, so dynamic linking isn't really
necessary. This paves the way for running System3.9 games on more
platforms.
NIGHTDLL is temporarily disabled, because many symbols conflict with the
SACT module.
kichikuou