Big bootstrapping change which greatly reduces the role of the modern
operating system in the bootstrapping process.

This will allow us to read from blkfs in tests.

Less noisy this way

The way is clear for complete stage1 bootstrapping on the RC2014
target!

It doesn't serve much purpose and takes up many precious bytes. And,
after all, parsed didn't do it either...

This allows us to remove forth/z80a.fs. Another big step towards
self-hosting!

Also, fix some PSP leaks related to LOAD.

It's not used

The former was only used in the peculiar context of "/emul". The
regular case is actually HERE pointing to RAMEND on boot.

Let's revisit the relinking approach, with LITA this time.
This reverts commit 6652125d47.

... instead of building boot.fs, and then z80c.fs/icore.fs in separate
passes. This strengten xcomp by making it support 2 completely separate
dicts (that is, the X dict is *not* connected to the system dict. The chain
now stops at EXIT def in boot.fs).

Memory mapping is a dead end too, solution has to be at a higher
level. xcomp is my new approach.

This was a dead end.

Not quite functional yet, but works in toy situations. The goal is to
concatenate RC2014's bootstrapped dict to the boot binary.

`xxd' is not available on all systems, and on others does not support
the `-i' flag. Since bin2c.sh relied on a tool that I can't seem to find
a compatible version of, I have included a simple, portable replacement in C.

Usage remains the same:
bin2c ARRAYNAME < inputfile > outputfile.

This change is also reflected in emul/Makefile.

This should help with the bootstrapping of non-emulated environment.
For example, I have a problem with the RC2014: I can't send it
bootstrap info until the ACIA is up. I need to find a way...

To update LATEST offset more easily. Will be useful for recipes.

All "stop pings" are now explicitly made at appropriate places. This
fixes a problem I've introduced in the last commit where RAM+ was
unexpectedly part of a stable ABI because of "HERE" usage in dummy.fs.

This system will, anyways, soon change because boot.bin and z80c.bin
will be built during the same process (but there's a bit of retooling
to do before I get there).

This commit cuts Forth's dependency on zasm. It now self-assembles
its own boot-binary! Things are a bit messy now, I'll clean up
later.

Make LATEST configurable through a value in the binary instead of through
a ZASM constant. This enables the simple concatenation of compiled dicts and
simplifies the build process.

Now we're seriously getting into real boostrapping territory...

This requires us to significantly adjust our build process, which
now has 3 stages.

The goal being to add a new native code dict staging phase.

This should help with upcoming challenges in bootstrapping z80 code
compiled through Forth.

The commit ended up being much bigger than anticipated. This was a long thread
of underlying complexities. This lead to the creation of interesting concepts
such as (sysv).

It's not really an App.