[Notion-devel] Proposed patch to do away with system-inc.mk.

[Etan R. <de...@un...>]

system-inc.mk was added (as far as I can recall and discern from what it
does) added to support the autotool build method for ion (which was a
third-party contribution, never worked all that well, and didn't work for
very long).

As such system-inc.mk doesn't serve much useful purpose at this point (the
ac/system-ac.mk file that it references hasn't existed, or been creatable,
in ages).

I'd like to get rid of it. That measns pulling the two include lines into
every Makefile that currently includes system-inc.mk.

Attached is a patch which does that. If this seems acceptable I'll commit
and push it.

I didn't want to make a change this big without checking (the rest of the
build stuff I've done has been comparatively minor).

    -Etan