7842 - new directory organization

Baremetal is now the default build target and therefore has its sources
at the top-level. Baremetal programs build using the phase-2 Mu toolchain
that requires a Linux kernel. This phase-2 codebase which used to be at
the top-level is now under the linux/ directory. Finally, the phase-2 toolchain,
while self-hosting, has a way to bootstrap from a C implementation, which
is now stored in linux/bootstrap. The bootstrap C implementation uses some
literate programming tools that are now in linux/bootstrap/tools.

So the whole thing has gotten inverted. Each directory should build one
artifact and include the main sources (along with standard library). Tools
used for building it are relegated to sub-directories, even though those
tools are often useful in their own right, and have had lots of interesting
programs written using them.

A couple of things have gotten dropped in this process:
  - I had old ways to run on just a Linux kernel, or with a Soso kernel.
    No more.
  - I had some old tooling for running a single test at the cursor. I haven't
    used that lately. Maybe I'll bring it back one day.

The reorg isn't done yet. Still to do:
  - redo documentation everywhere. All the README files, all other markdown,
    particularly vocabulary.md.
  - clean up how-to-run comments at the start of programs everywhere
  - rethink what to do with the html/ directory. Do we even want to keep
    supporting it?

In spite of these shortcomings, all the scripts at the top-level, linux/
and linux/bootstrap are working. The names of the scripts also feel reasonable.
This is a good milestone to take stock at.

1 files changed, 0 insertions, 28 deletions

diff --git a/apps/README.md b/apps/README.md
deleted file mode 100644
index 665632c2..00000000
--- a/apps/README.md
+++ /dev/null
@@ -1,28 +0,0 @@
-Some apps written in SubX and Mu. Check out:
-
-* `tile`: [An experimental live-updating postfix shell environment](https://mastodon.social/@akkartik/105108305362341204)
-  that updates as you type. Prototype. Look at this to see what is currently
-  possible, not how I recommend building software.
-
-  <img alt='tile app' src='../html/rpn5.png' width='500px'>
-
-* `browse`: [A text-mode browser for a tiny subset of Markdown](https://mastodon.social/@akkartik/104845344081779025).
-
-* `ex*`: small stand-alone examples that don't need any of the shared code at
-  the top-level. They each have a simple pedagogical goal. Read these first.
-
-* `factorial*`: A simple program to compute factorials in 5 versions, showing
-  all the different syntax sugars and what they expand to.
-
-* Code unique to phases of our build toolchain:
-  * Core SubX: `hex`, `survey_elf`, `pack`, `dquotes`, `assort`, `tests`
-  * Syntax sugar for SubX: `sigils`, `calls`, `braces`
-  * More ambitious translator for a memory-safe language (in progress): `mu`
-
-* Miscellaneous test programs.
-
-All SubX apps include binaries. At any commit, an example's binary should be
-identical bit for bit with the result of translating the corresponding `.subx`
-file. The binary should also be natively runnable on a Linux system running on
-Intel x86 processors, either 32- or 64-bit. If either of these invariants is
-violated, it's a bug.