Remove the notion of "sys*"

- This idea originates from very early in the project and was, at the
  time, a very easy way to categorise things.
- Now, it doesn't really make much sense - it is fairly arbitary, often
  occuring when there is a change in kernel, but not from builder-hex0
  to fiwix, and sysb is in reality completely unnecessary.
- In short, the sys* stuff is a bit of a mess that makes the project
  more difficult to understand.
- This puts everything down into one folder and has a manifest file that
  is used to generate the build scripts on the fly rather than using
  coded scripts.
- This is created in the "seed" stage.

stage0-posix -- (calls) --> seed -- (generates) --> main steps

Alongside this change there are a variety of other smaller fixups to the
general structure of the live-bootstrap rootfs.

- Creating a rootfs has become much simpler and is defined as code in
  go.sh. The new structure, for an about-to-be booted system, is

/
-- /steps (direct copy of steps/)
-- /distfiles (direct copy of distfiles/)
-- all files from seed/*
-- all files from seed/stage0-posix/*

- There is no longer such a thing as /usr/include/musl, this didn't
  really make any sense, as musl is the final libc used. Rather, to
  separate musl and mes, we have /usr/include/mes, which is much easier
  to work with.
- This also makes mes easier to blow away later.
- A few things that weren't properly in packages have been changed;
  checksum-transcriber, simple-patch, kexec-fiwix have all been given
  fully qualified package names.
- Highly breaking change, scripts now exist in their package directory
  but NOT WITH THE packagename.sh. Rather, they use pass1.sh, pass2.sh,
  etc. This avoids manual definition of passes.
  - Ditto with patches; default directory is patches, but then any patch
    series specific to a pass are named patches-passX.

sysc/gcc-4.7.4/patches/0003-unwind-fix-for-musl.patch

@@ -1,35 +0,0 @@
-SPDX-FileCopyrightText: 2022 Dor Askayo <dor.askayo@gmail.com>
-SPDX-FileCopyrightText: 2015 Gregor Richards <gregor.richards@uwaterloo.ca>
-SPDX-FileCopyrightText: 2015 Szabolcs Nagy <szabolcs.nagy@arm.com>
-
-SPDX-License-Identifier: GPL-2.0-or-later
-
-Backported from upstream commit 15aa7b447218e45da835472bbf4740ae00db9982
-
-unwind fix for musl
-
-2015-04-22  Gregor Richards  <gregor.richards@uwaterloo.ca>
-	    Szabolcs Nagy  <szabolcs.nagy@arm.com>
-
-	* unwind-dw2-fde-dip.c (USE_PT_GNU_EH_FRAME): Define it on
-	Linux if target provides dl_iterate_phdr.
-
-Co-Authored-By: Szabolcs Nagy <szabolcs.nagy@arm.com>
-
-From-SVN: r222328
-
---- libgcc/unwind-dw2-fde-dip.c
-+++ libgcc/unwind-dw2-fde-dip.c
-@@ -53,6 +53,12 @@
- # define USE_PT_GNU_EH_FRAME
- #endif
- 
-+#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
-+    && defined(TARGET_DL_ITERATE_PHDR) \
-+    && defined(__linux__)
-+# define USE_PT_GNU_EH_FRAME
-+#endif
-+
- #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
-     && defined(__FreeBSD__) && __FreeBSD__ >= 7
- # define ElfW __ElfN