AROS: ABI compatibility update AROSSupportBase (ABI/API/BC break)

These changes break API/Binary Compatibility between ABIv0 and ABIv1.

Field stdOut is replaced by undefined field named _pad for ABIv1 while (still) being present as stdOut for ABIv0.

Field DebugConfig is completely removed from ABIv1 (still present for ABIv0).

If your code depends on either of these two fields then you need to make appropriate changes when compiling for ABIv1.

Removing dependency on either of these two mentioned fields is preferred.

Both RTL (execd.inc) and unit (exec.pas) are updated.

See also https://github.com/aros-development-team/AROS/commit/194cc5e1c52a9dc67aa2275c8acb26673e454757