"make all", and then reference them there during the actual tests.  This
makes the handling of these files more parallel to that of regress.so,
and in particular simplifies use of the regression tests outside the
original build tree.  The PGDG and Red Hat RPMs have been doing this via
patches for a very long time.  Inclusion of the change in core was requested
by Jørgen Austvik of Sun, and I can't see any reason not to.

I attempted to fix the MSVC scripts for this too, but they may need
further tweaking ...

in .bat simply did not work, and it called them in the wrong order,
some several times, and some not at all. So this unrolls all subroutine
calls.

This should fix the issues with clean deleting the wrong files reported
by Dave Page.

While at it, add the "clean dist" option to act like "make distclean",
and no longer remove the flex/bison output files by default. This shuold
fix the problem reported by Pavel Golub in bug #3909.

test outputs.

Fixes builds from tarballs where the file is pre-generated.

Yoshiyuki Asaba

regression driver into two parts and reusing half of it. Required to
run ECPG tests without a shell on MSVC builds.

Fix ECPG thread tests for MSVC build (incl output files).

Joachim Wieland and Magnus Hagander

what each script does.

clean script to properly clean up the result of it.