* More but still incomplete support for mkcl and cormanlisp.

This allows the examples to be created without having to install
an XCVB. The primary implementation is in bootstrap.lisp and
additional code in driver.lisp.
+ The created XCVB is made with one of the supported lisp
implementations even though the enclosing lisp invocation might
not be.
+ Refactored lisp-invocation into its own package.
+ The cache-description file contains notes about how the cache
should function. The cache is both the multi-user cache as in
distcc, ccache, etc, but also the user specific workspace for
where to dump fasl files and whatnot.

Fixes to the bridge and to CMUCL, ECL, SCL support that make it work better.

* get rid of no-asdf
* remove shell stuff from string-escape (moved to driver)
* fixed comments in lisp-invocation.lisp to be more correct.

Update documentation.
Fix implicit build (default without --build).

(xcvb-unit-tests::test-simple-build :implementation 'allegro)

(xcvb-unit-tests::test-simple-build :implementation 'lispworks)

Try to make it work with gcl - but gcl fails to compile driver.lisp.

On Unix: abcl, allegro, ccl, clisp, ecl, gcl, sbcl, scl, xcl
On Windows: allegro, sbcl.

Very portable, but serial support only, no parallel queueing for now.
Also, driver.lisp now has *fatal-conditions* like *uninteresting-conditions*
instead of *fatal-condition*.
Added support for driving all the current actively maintained CL implementations.

Converted the makefile style transformation of a computation into
a command into a more generalized external command form of the
computations.  Condensed functionality from driver-commands.lisp and
makefile-backend.lisp into external-commands.lisp. This is because at
this time both the makefile backend and a new run-program back end will
use them.

Added a run-program based backend called "simple-build" which will execute
the commands necessary to build the dependencies in the graph. At this
time it is a serial execution of the dependencies. The functionality is
not yet complete and currently broken as of this checkin.

Fixed up the xcvb.asd file to denote the new dependencies.

Comments re: lisp-invocation of cmucl and scl.

However, we don't interact correctly with cl-launch
to produce a standalone executable from an ECL executable image.
Presumably, we ought to support builds as .a files
instead of just as executable images. Future work.
At least, a proof of concept is here.

TODO for ECL: distinguish linkable object files from loadable shared objects.

to avoid staging conflict with the variable used to start XCVB itself,
when compiled with CCL. Similarly with $XSCBL, etc. Sigh.

Package with newer ASDF and C-L-A.
Drop support for old SBCL's without --no-userinit, makes it easier on Windows SBCL.

Requires cl-launch 2.22, a closer2mop update.
(Changes actually by fare)

  * tweaked dependencies and moved code around in a vain attempt to avoid
   "undefined function" warnings, until I decided to DTRT and start writing
   a handler for warnings.

  * finally extended the driver to deal somewhat with catching warnings,
   getting inspiration from ITA's qres-build. However, some warnings are
   deferred and will need to be dumped in a side-file and handled later.

  * Make no-asdf support for SBCL more robust: 1- add clean-up forms that
   both remove the asdf module provider gunk and ensure that re-loading asdf
   will reinstate it. 2- use --sysinit /dev/null so that the /etc/sbcl*rc
   won't bork on lack of ASDF.

  * update TODO.

These options will allow me to handle Lisp *feature*s correctly.

Example:
xcvb.mk: ${LISP_SOURCES} setup.lisp ${LISP_BIN}
	xcvb make-makefile --setup /xcvb/setup --build /xcvb --target-lisp-impl ${LISP_IMPL} --target-lisp-bin ${LISP_BIN}

* ensure installation directories exist
* add module forms to every file
* fix nickname registration
* add an eval-when for compile-time functions
* add support for xcvb.mk in the main Makefile
* trivially tested the result

* package the command-line-arguments library
* better support asdf dependencies
* put a command interpreter in the driver
* put objects in ./obj/ directory in Makefile backend
* use relative path when possible in Makefile backend
* use ./ in front of executables in a relative path
* refactor the :create-image command so it might possibly work with ECL

* Fix name resolution to allow relative naming of BUILDs as well as files.
* Add load capability to lisp-invocation-arglist (to make it easy to load a driver).
* Documentation update, notably re: TODO items.

It won't even compile, but at least other people can see where I'm at.
Once again, see instructions in README to checkout a working version of the 0.11 prototype.

For the working prototype, please use
	git checkout xcvb_0.11

In this commit:
* massive refactoring of internals according to the "grain" design in TODO.
* implementing search path and naming for multiple builds.
* Documentation update including slides for ILC'09.

* Support user specification of dependencies for the initial build image.
* Add :load-source dependencies.
* Traverse in the correct order (reverse from what push creates)
* need to install initial Lisp files somewhere.
* correcly get asdf system dependencies from original systems
* update exscribe examples
* fix driver some more
* fix lack of backquote in define-lisp-implementation (duh),
 also fix use of sbcl's quit.
* remove some more remnants of the escaped output-path
* When we say we use cfasls, mean it.
* Find staged executables in current directory
* Rename default output from Makefile.xcvb to xcvb.mk

* Fix bugs: got the sort to actually work, fix driver,
* moved the grovel tmp dir to the cache (depends on patch to ADG)
* started a compilation example -- fails for now (needs a way to tweak *central-registry*)
* refactored how multiple lisp implementations are handled.
* excised sbrody's painfully coded pre-escaping --
 will have to account for ${FASL} in a cleaner way if ever.
* re-worked the makefile generation somewhat.