[kernel][cpp] convert a few more libs (debug, version) to cpp

Also ran the formatter at the same time, since these are such simple
files.

Change-Id: Ib9f80e5c1ff9f98517beea93f6cd42aa75e20576

[make][version] Remove never-set OFFICIAL_BUILD conditional

Change-Id: Iea50df225cc30d5fb7091553b7238140a297d8b9

[build] Magenta host support fixes

- Invoke scripts with an explicit shell path.
- Use bash+dash-compatible integer variables.

Change-Id: I31a83a9b961950ab3cc5ccf9a09c0daed99776b0

[make] make sure lib/version's rule doesn't depend on .PHONY

This had the effect of making all PHONY rules always get built.

Change-Id: I4c417c62deeeff8f96f8f1d2438de92c5ae6178d

[build] allow source files to be used by multiple modules

You will want to "make spotless" after picking up this change.

The most noticable change is that module build results live under
$BUILDDIR/$SHORTNAME/... where SHORTNAME is the module name without
the top level prefix (kernel, system, third_party). This has the
nice side-effect of being able to find build results without worrying
about which top level tree they came from. Module short names must
be unique so they will not collide.

Previously object files (individual .o's) ended up in
$BUILDDIR/$SOURCEPATH/file.c.o which meant if two modules attempted
to use the same source file the object file would collide. Object
files are now at $BUILDDIR/$SHORTNAME/$SOURCEPATH/file.c.o and thus
do not collide and may be built with different flags, includes, etc
in each module that uses them.

This enables, for example, building a library for both kernel and
userspace without needing multiple copies of the source.

Some other cleanup:
- cluster config headers and bootfs bits together lexigraphically
- don't generate source and include listing files
- build bootserver and loglistener into $BUILDDIR/tools as part
of the build instead of via a one-off Makefile in tools/

Change-Id: Id97264e14222b5e051c54718bb1158e0d0f6f088

[magenta] Initial commit