This patch should complete the addition of static qualifiers to all
MAME symbols that aren't explicitly exported. It primarily handles
generated code (e.g. amspdwy.c), plus a handful of cases I'd
previously missed and some new cases introduced in the last update.
One interesting bit was the discovery that the 32-bit scanline
routines in drawgfx.c are unused. I debated eliminating them but
decided instead to just export them. Various internal drawgfx
functions were conditionally removed by examining a new RAW define,
although one routine (blockmove_8toN_alphaone) was determined to be
dead code.
While investigating constifying MESS, I came across a few core APIs
that were missing const qualifiers which this patch fixes. I also
consted up tx1.c while I was at it.
