make functions in EXTRA_DIST are misparsed

[Andrew Suffield]

If I put make functions into EXTRA_DIST, or even something that is
evaluated with a := and then put into EXTRA_DIST, spurious directories
are created in the distdir.

Example:
test_cases := $(wildcard dancer.*/*.cs) $(wildcard dancer.*/*.pl)
EXTRA_DIST := README config/unix.pl $(test_cases)

A directory $(distdir)/dancer.* is created; the shell function is not
expanded.

I work around it like this:
dist-hook:
        rmdir -- $(distdir)/dancer.\*

The problem appears to be around line 4100-4200 of automake, starting
from this part:
    # Scan EXTRA_DIST to see if we need to distribute anything from a
    # subdir.  If so, add it to the list.  I didn't want to do this
    # originally, but there were so many requests that I finally
    # relented.

Presumably variable_value_as_list_recursive is hopelessly confused by
make functions. Since everything else works if you ignore this one
error, I would be inclined to throw away make functions entirely, on
the basis that solving the problem is somewhere between "too hard" and
"impossible", and leaving it to the author of Makefile.am to create
directories as needed in this case.

[I used to explicitly list all the test scripts, but then you have to
remember to add new ones, or else they silently disappear from the
distribution and nothing notices].

-- 
  .''`.  ** Debian GNU/Linux ** | Andrew Suffield
 : :' :  http://www.debian.org/ | Dept. of Computing,
 `. `'                          | Imperial College,
   `-             -><-          | London, UK

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