New script for deferred warnings.

Also, propagate around previous improvements to stream slurping.
Fix some test cases.

Also, make script re-loadable in a debug session.

Better version mangling helpers.

Image: for compatibility with existing CL practice,
the call the entry-point *without* arguments rather than with C command line.

Don't key upgrade attempt on source-registry, since things can also change
in the central-registry, etc.
Also rename required-files to direct-dependency-files
Improve the new convenience function pattern to work with operation initargs.
Implement getcwd on all platforms.
Actually catch sb-grovel messages.

Tests: make u l=ecl instead of make test-upgrade lisp=ecl
Tests: put the setup around the script, not inside;
Tests: start using globals, much easier for debugging

Also, have convenience methods for operation and component designators.
Enhance the incidental traversal functions.
Move compile-file error handling to lisp-build.

Passes tests on CCL and SBCL.

(equal #p"ccl:" #p"/") ==> T. Yikes.

jyknight will be happy. Passes test, when still resolving.

also use asdf-defsystem as the name for packaging.

Also remove some forgotten debugging statement,
clean the asd somewhat.

unless we're backward compatible.

Still not used by ASDF itself.

Also, don't use compile-file-pathname after all, it's a bad idea,
since we may be loading a .asd from within an eval-when during a compile-file,
but we won't be compiling the .asd.

Have one bigger lisp script to replace several shell scripts.

Tests now pass on SBCL.

A system named foo/bar will be looked up in a registered file foo.asd.
This makes it possible to sensibly name several systems in a .asd file
and still have asdf find them all by name.
We now use it to not have the asdf header be part of asdf-driver.

A new generic operation build-op makes it possible to deal with
the fact that the default operation for systems need not be load-op,
yet that the end-user does not want to have to know the exact operation
for each of the system he uses.

ensure-pathname has been improved again, and its clients tweaked.

remove-keys was made more sensible by using EQL rather than STRING-EQUAL.

:version need not take the first form in a file, but can take
a path to a subform. This makes it possible to get the exact subform
in a Lisp source file that has the string.
See SUB-OBJECT for how these paths work.

Cleanup of the semantics of ENSURE-FUNCTION on CONSes: use APPLY, not EVAL.

Some attempts at making things work for ABCL and CLISP.

Also, fix the generate-asdf.asd system.

Move things around and rename functions to improve backward compatibility.
The driver now has its own backward-compatibility file.

* Pathname support has been cleaned up, yet again,
 extending and renaming COERCE-PATHNAME into PARSE-UNIX-NAMESTRING,
 also ENSURE-PATHNAME, many docstrings, and plenty of small enhancements.
* Bundles were refactored to take advantage of the new, more sensible,
 component-depends-on semantics.
* Image support was cleaned up again, and program-op was implemented
 to produce a standalone executable on supported platforms;
 a working hello-world-example is included amongst tests.
* The *compile-file-function* indirection was removed, with the
 ECL and MKCL object file support
 being folded into compile-file* instead.
* systems now can have NIL as component-pathname,
 instead of providing a non-sensible bogus pathname
 when no sensible pathname was determined.
 Most of our pathname functions have sensible default behavior
 when provided NIL instead of a pathname as an argument.