M302de: BC: borlandify seg072
M302de: BC: ds_write() functions return the written value

The return value from ds_write() functions return now the value
the have written to the datasegment.
This way we can recompile assignments of the type:

/* global variables */
int v1, v2;

void foo() {
	v2 = v1 = 0;
}

instead of doing each assignment seperately, like:

void foo() {
	v1 = 0;
	v2 = 0;
}
M302de: BC: use the new feature of ds_write funnctions
M302de: BC: add increment / decrement for pointers
M302de: BC: use new features of inc/dec
M302de: BC: Bugfix: correct loop start

This should be nothing critical, but now seg047 is
completely borlandified and identical.
M302de: BC: seg047 is now complete