This includes several improvements to the link flags, link script,
common makefile, etc..
Previously bss initialization in m68k start was incorrect. m68k can
now call static initializers if necessary.
This makes the m68k make rules usable from other makefiles.
This also adds scsp start address macros.
The sound.c example-fragment is deleted, as a better version now exists
in saturn-examples.
- add code loading for m68k
- incomplete scsp experiments
- the register definitions should be fairly complete,
though I did not produce actual sound yet
- fix type.h definitions
- incomplete cdblock register definitions
