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

1 files changed, 1 insertions, 1 deletions

diff --git a/configure b/configure
index cc6471bba6..52834e9545 100755
--- a/configure
+++ b/configure
@@ -7866,7 +7866,7 @@ perl_ccflags=`$PERL -MConfig -e 'print $Config{ccflags}'`
 $as_echo "$perl_ccflags" >&6; }
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for CFLAGS to compile embedded Perl" >&5
 $as_echo_n "checking for CFLAGS to compile embedded Perl... " >&6; }
-perl_embed_ccflags=`$PERL -MConfig -e 'foreach $f (split(" ",$Config{ccflags})) {print $f, " " if ($f =~ /^-D[^_]/)}'`
+perl_embed_ccflags=`$PERL -MConfig -e 'foreach $f (split(" ",$Config{ccflags})) {print $f, " " if ($f =~ /^-D[^_]/ || $f =~ /^-D_USE_32BIT_TIME_T/)}'`
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $perl_embed_ccflags" >&5
 $as_echo "$perl_embed_ccflags" >&6; }