Update Amiga makefiles to include Bzip2 support. Currently, it provides FT_Stream_OpenBzip2() that returns unimplemented error always, to prevent unresolved symbol error for the applications designed for Unix systems. * builds/amiga/makefile: Include bzip2.ppc.o built from ftbzip2.c. * builds/amiga/makefile.os4: Include bzip2.o built from ftbzip2.c. * builds/amiga/smakefile: Ditto.