PL/Perl portability fix: absorb relevant -D switches from Perl.

Back-patch of commit 3c163a7,
which see for more info.

Also throw in commit b4cc35f,
so Coverity doesn't whine about the back branches.

Ashutosh Sharma, some adjustments by me

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

Author: tglsfdc

config/perl.m4

@@ -49,6 +49,31 @@ AC_DEFUN([PGAC_CHECK_PERL_CONFIGS],
 [m4_foreach([pgac_item], [$1], [PGAC_CHECK_PERL_CONFIG(pgac_item)])])
 
 
+# PGAC_CHECK_PERL_EMBED_CCFLAGS
+# -----------------------------
+# We selectively extract stuff from $Config{ccflags}.  We don't really need
+# anything except -D switches, and other sorts of compiler switches can
+# actively break things if Perl was compiled with a different compiler.
+# Moreover, although Perl likes to put stuff like -D_LARGEFILE_SOURCE and
+# -D_FILE_OFFSET_BITS=64 here, it would be fatal to try to compile PL/Perl
+# to a different libc ABI than core Postgres uses.  The available information
+# says that all the symbols that affect Perl's own ABI begin with letters,
+# so it should be sufficient to adopt -D switches for symbols not beginning
+# with underscore.
+# For debugging purposes, let's have the configure output report the raw
+# ccflags value as well as the set of flags we chose to adopt.
+AC_DEFUN([PGAC_CHECK_PERL_EMBED_CCFLAGS],
+[AC_REQUIRE([PGAC_PATH_PERL])
+AC_MSG_CHECKING([for CFLAGS recommended by Perl])
+perl_ccflags=`$PERL -MConfig -e ['print $Config{ccflags}']`
+AC_MSG_RESULT([$perl_ccflags])
+AC_MSG_CHECKING([for CFLAGS to compile embedded Perl])
+perl_embed_ccflags=`$PERL -MConfig -e ['foreach $f (split(" ",$Config{ccflags})) {print $f, " " if ($f =~ /^-D[^_]/)}']`
+AC_SUBST(perl_embed_ccflags)dnl
+AC_MSG_RESULT([$perl_embed_ccflags])
+])# PGAC_CHECK_PERL_EMBED_CCFLAGS
+
+
 # PGAC_CHECK_PERL_EMBED_LDFLAGS
 # -----------------------------
 # We are after Embed's ldopts, but without the subset mentioned in

configure

@@ -670,6 +670,7 @@ python_version
 python_majorversion
 PYTHON
 perl_embed_ldflags
+perl_embed_ccflags
 perl_useshrplib
 perl_privlibexp
 perl_archlibexp
@@ -7511,6 +7512,18 @@ documentation for details.  Use --without-perl to disable building
 PL/Perl." "$LINENO" 5
   fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for CFLAGS recommended by Perl" >&5
+$as_echo_n "checking for CFLAGS recommended by Perl... " >&6; }
+perl_ccflags=`$PERL -MConfig -e 'print $Config{ccflags}'`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $perl_ccflags" >&5
+$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[^_]/)}'`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $perl_embed_ccflags" >&5
+$as_echo "$perl_embed_ccflags" >&6; }
+
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for flags to link embedded Perl" >&5
 $as_echo_n "checking for flags to link embedded Perl... " >&6; }
 if test "$PORTNAME" = "win32" ; then

configure.in

@@ -928,6 +928,7 @@ You might have to rebuild your Perl installation.  Refer to the
 documentation for details.  Use --without-perl to disable building
 PL/Perl.])
   fi
+  PGAC_CHECK_PERL_EMBED_CCFLAGS
   PGAC_CHECK_PERL_EMBED_LDFLAGS
 fi
 

contrib/hstore_plperl/Makefile

@@ -43,4 +43,4 @@ endif
 # last, probably because it sometimes contains some header files with names
 # that clash with some of ours, or with some that we include, notably on
 # Windows.
-override CPPFLAGS := $(CPPFLAGS) -I$(perl_archlibexp)/CORE
+override CPPFLAGS := $(CPPFLAGS) $(perl_embed_ccflags) -I$(perl_archlibexp)/CORE

src/Makefile.global.in

@@ -298,6 +298,7 @@ else
 endif
 perl_archlibexp		= @perl_archlibexp@
 perl_privlibexp		= @perl_privlibexp@
+perl_embed_ccflags	= @perl_embed_ccflags@
 perl_embed_ldflags	= @perl_embed_ldflags@
 
 # Miscellaneous

src/pl/plperl/GNUmakefile

@@ -12,7 +12,11 @@ override CPPFLAGS += -DPLPERL_HAVE_UID_GID
 override CPPFLAGS += -Wno-comment
 endif
 
-override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS) -I$(perl_archlibexp)/CORE
+# Note: we need to make sure that the CORE directory is included last,
+# probably because it sometimes contains some header files with names
+# that clash with some of ours, or with some that we include, notably on
+# Windows.
+override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS) $(perl_embed_ccflags) -I$(perl_archlibexp)/CORE
 
 rpathdir = $(perl_archlibexp)/CORE
 

src/pl/plperl/plperl.c

@@ -3248,12 +3248,18 @@ plperl_return_next_internal(SV *sv)
 
 		/*
 		 * This is the first call to return_next in the current PL/Perl
-		 * function call, so memoize some lookups
+		 * function call, so identify the output tuple descriptor and create a
+		 * tuplestore to hold the result rows.
 		 */
 		if (prodesc->fn_retistuple)
 			(void) get_call_result_type(fcinfo, NULL, &tupdesc);
 		else
+		{
 			tupdesc = rsi->expectedDesc;
+			/* Protect assumption below that we return exactly one column */
+			if (tupdesc == NULL || tupdesc->natts != 1)
+				elog(ERROR, "expected single-column result descriptor for non-composite SETOF result");
+		}
 
 		/*
 		 * Make sure the tuple_store and ret_tdesc are sufficiently
@@ -3301,20 +3307,20 @@ plperl_return_next_internal(SV *sv)
 	}
 	else
 	{
-		Datum		ret;
-		bool		isNull;
+		Datum		ret[1];
+		bool		isNull[1];
 
-		ret = plperl_sv_to_datum(sv,
-								 prodesc->result_oid,
-								 -1,
-								 fcinfo,
-								 &prodesc->result_in_func,
-								 prodesc->result_typioparam,
-								 &isNull);
+		ret[0] = plperl_sv_to_datum(sv,
+									prodesc->result_oid,
+									-1,
+									fcinfo,
+									&prodesc->result_in_func,
+									prodesc->result_typioparam,
+									&isNull[0]);
 
 		tuplestore_putvalues(current_call_data->tuple_store,
 							 current_call_data->ret_tdesc,
-							 &ret, &isNull);
+							 ret, isNull);
 	}
 
 	MemoryContextSwitchTo(old_cxt);

src/tools/msvc/Mkvcbuild.pm

@@ -516,7 +516,26 @@ sub mkvcbuild
 		my $plperl =
 		  $solution->AddProject('plperl', 'dll', 'PLs', 'src/pl/plperl');
 		$plperl->AddIncludeDir($solution->{options}->{perl} . '/lib/CORE');
-		$plperl->AddDefine('PLPERL_HAVE_UID_GID');
+
+		# Add defines from Perl's ccflags; see PGAC_CHECK_PERL_EMBED_CCFLAGS
+		my @perl_embed_ccflags;
+		foreach my $f (split(" ",$Config{ccflags}))
+		{
+			if ($f =~ /^-D[^_]/)
+			{
+				$f =~ s/\-D//;
+				push(@perl_embed_ccflags, $f);
+			}
+		}
+
+		# XXX this probably is redundant now?
+		push(@perl_embed_ccflags, 'PLPERL_HAVE_UID_GID');
+
+		foreach my $f (@perl_embed_ccflags)
+		{
+			$plperl->AddDefine($f);
+		}
+
 		foreach my $xs ('SPI.xs', 'Util.xs')
 		{
 			(my $xsc = $xs) =~ s/\.xs/.c/;
@@ -599,7 +618,11 @@ sub mkvcbuild
 			'hstore_plperl', 'contrib/hstore_plperl',
 			'plperl',        'src/pl/plperl',
 			'hstore',        'contrib/hstore');
-		$hstore_plperl->AddDefine('PLPERL_HAVE_UID_GID');
+
+		foreach my $f (@perl_embed_ccflags)
+		{
+			$hstore_plperl->AddDefine($f);
+		}
 	}
 
 	$mf =