compressor fixup section.

bin/%.bin target.

bytes of useless zeroes in the final image.

link-time check for section overlaps.  (In order to avoid wasting
space in the executable image, .bss16 will overlap with the following
section, which is .text).

This reverts commit 9dc2515d7e.

I want "make" to actually build something.

start of the non-prefix blocks in the loaded image, and rely on the
image ordering.  This should make introducing compression much easier.

"rep movsb".