variable warning on Windows, improve comment.

trying BIO functions.
Helps problem with older versions of OpenSSL that lacks error
stack functions and would show an incorrect error message for
file-not-found-or-not-openable. The problem may still exist for
other errors, but file open error is by far the most common one.

Set pgtypes library version to 3.0.
Set compat library version to 3.0.

we restricted exports from ecpglib.

on MSVC.

Fix strange nonstandard version of __stdcall specifyer in thread
tests on win32.

Created export list for ecpglib.

the 'overview' and 'incompatibilities' summary lists remain to be
written.  But I think all the raw info is there (indeed maybe too
verbose).

make sure that a CPU option is actually chosen.

Hiroshi Saito

descriptor handling

OpenSSL libraries --- just don't call them if they're not there.  This
might possibly lead to misleading error messages, but we'll just have
to live with that.

This fixes potential crashes on old versions of OpenSSL and the requirement on
"Applink" in new versions when building with MSVC and using different
runtimes.

Dave Page with fixes from me.

compiler --- at least on ARM, it does.  I suspect that the varvarlena patch
has been creating larger-than-intended toast pointers all along on ARM,
but it wasn't exposed until the latest tweak added some Asserts that
calculated the expected size in a different way.  We could probably have
fixed this by adding __attribute__((packed)) as is done for ItemPointerData,
but struct varattrib_pointer isn't really all that useful anyway, so it
seems cleanest to just get rid of it and have only struct varattrib_1b_e.
Per results from buildfarm member quagga.

Hiroshi Saito

Hannes Eder

explicitly.  This means a TOAST pointer takes 18 bytes instead of 17 --- still
smaller than in 8.2 --- which seems a good tradeoff to ensure we won't have
painted ourselves into a corner if we want to support multiple types of TOAST
pointer later on.  Per discussion with Greg Stark.

ITAGAKI Takahiro's patch.

while the restore_command does its thing, then 'recovering XXX' while
processing the segment file.  These operations are heavyweight enough
that an extra PS display set shouldn't bother anyone.