The issue fixed is that most Lisps don't like
*default-pathname-defaults* being a logical-pathname.
Added a test for logical-pathname functionality;
it all works on CCL, and works better on other Lisps after the fix,
but there are still logical-pathname issues on SBCL, CLISP and more.
Also, a package cleanup of our test suite.

Minimal documentation.

as expanded from the read-conditionals. Use (progn :default :utf-8) instead.

that's causing a warning with SBCL.

and the implementation-dependent external-format arguments.
Actually, only add a default encoding/external-format pair and
a hook to allow for an extension that would define more.
Based on asdf-devel@ discussion thread with Orivej Desh and Robert Goldman.

External format is specified via keyword :external-format per system
or per its component, the latter taking precedence.  The value is
passed then as :external-format to #'load and #'compile-file.

When unspecified, external-format defaults to UTF-8.

(in the end, the issue was not in ASDF, but the refactoring remains).

When specifying a function as output-translation,
we accept either (:function symbol) or
(:function (lambda (pathname absolute-source) ...)
The second case wasn't properly handled.
Minimal testing included.
спасибо Сергей.

WEAKLY-DEPENDS-ON needed to pass the ERROR-P NIL to FIND-SYSTEM in order
to behave properly.

Added documentation for previously-undocumented weakly-depends-on.

From bug report by Rupert Swarbrick.

Thanks to Sergey Katrevich for tracking the bad parenthesization.

for smoother upgrade. Update web page.

Apparently, ecl doesn't like (change-class x 'standard-object).

to properly deal with paths gotten with GETENV.
Bug introduced with subpathname in 2.017.27. Should fix debbugs #647544:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=647544#10
Thanks to Desmong O. Chang.

and add more extensions to clean in the Makefile.

they break the r-i contract and mess up with asdf-dependency-grovel.

in view of using it in a system-granular parallelizing backend.

Don't defparameter *system-definition-search-functions*, use defvar and fixup.
Clear *systems-being-defined* when upgrading asdf,
but re-find them immediately because they may be needed
as part of a higher operation.
Thanks to Nikodemus for reporting the bug while using quicklisp.

of some internal functions though they may be in the continuation
of an asdf upgrade, because asdf could be loaded by a .asd file
we load while finding a system for a dependency.
Solution: unintern the symbols during an upgrade.