pgsql: Absorb -D_USE_32BIT_TIME_T switch from Perl, if relevant.

Absorb -D_USE_32BIT_TIME_T switch from Perl, if relevant.

Commit 3c163a7fc's original choice to ignore all #define symbols whose
names begin with underscore turns out to be too simplistic. On Windows,
some Perl installations are built with -D_USE_32BIT_TIME_T, and we must
absorb that or we get the wrong result for sizeof(PerlInterpreter).

This effectively re-reverts commit ef58b87df, which injected that symbol
in a hacky way, making it apply to all of Postgres not just PL/Perl.
More significantly, it did so on *all* 32-bit Windows builds, even when
the Perl build to be used did not select this option; so that it fails
to work properly with some newer Perl builds.

By making this change, we would be introducing an ABI break in 32-bit
Windows builds; but fortunately we have not used type time_t in any
exported Postgres APIs in a long time. So it should be OK, both for
PL/Perl itself and for third-party extensions, if an extension library
is built with a different _USE_32BIT_TIME_T setting than the core code.

Patch by me, based on research by Ashutosh Sharma and Robert Haas.
Back-patch to all supported branches, as commit 3c163a7fc was.

Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/5a5c2feca3fd858e70ea348822595547e6fa6c15

Modified Files
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config/perl.m4 | 6 ++++--
configure | 2 +-
src/tools/msvc/MSBuildProject.pm | 9 ++-------
src/tools/msvc/Mkvcbuild.pm | 5 +++--
src/tools/msvc/VCBuildProject.pm | 10 ++--------
5 files changed, 12 insertions(+), 20 deletions(-)