Use perl warnings pragma consistently

We've had a mixture of the warnings pragma, the -w switch on the shebang
line, and no warnings at all. This patch removes the -w swicth and add
the warnings pragma to all perl sources missing it. It raises the
severity of the TestingAndDebugging::RequireUseWarnings  perlcritic
policy to level 5, so that we catch any future violations.

Discussion: https://postgr.es/m/20200412074245.GB623763@rfd.leadboat.com

contrib/intarray/bench/bench.pl

 #!/usr/bin/perl
 
 use strict;
+use warnings;
 
 # make sure we are in a sane environment.
 use DBI();

contrib/intarray/bench/create_test.pl

@@ -3,6 +3,8 @@
 # contrib/intarray/bench/create_test.pl
 
 use strict;
+use warnings;
+
 print <<EOT;
 create table message (
 	mid	int not null,

contrib/seg/seg-validate.pl

 #!/usr/bin/perl
 
 use strict;
+use warnings;
 
 my $integer = '[+-]?[0-9]+';
 my $real    = '[+-]?[0-9]+\.[0-9]+';

contrib/seg/sort-segments.pl

@@ -3,6 +3,7 @@
 # this script will sort any table with the segment data type in its last column
 
 use strict;
+use warnings;
 
 my @rows;
 

doc/src/sgml/mk_feature_tables.pl

-# /usr/bin/perl -w
+# /usr/bin/perl
 
 # doc/src/sgml/mk_feature_tables.pl
 
 use strict;
+use warnings;
 
 my $yesno = $ARGV[0];
 

src/backend/catalog/genbki.pl

-#!/usr/bin/perl -w
+#!/usr/bin/perl
 #----------------------------------------------------------------------
 #
 # genbki.pl

src/backend/utils/Gen_fmgrtab.pl

-#! /usr/bin/perl -w
+#! /usr/bin/perl
 #-------------------------------------------------------------------------
 #
 # Gen_fmgrtab.pl

src/backend/utils/mb/Unicode/UCS_to_BIG5.pl

@@ -25,6 +25,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_BIG5.pl';

src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl

@@ -14,6 +14,8 @@
 # and the "b" field is the hex byte sequence for GB18030
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl';

src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl

@@ -8,6 +8,8 @@
 # "euc-jis-2004-std.txt" (http://x0213.org)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl';

src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl

@@ -12,6 +12,8 @@
 # organization's ftp site.
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl';

src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl

@@ -17,6 +17,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl';

src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl

@@ -18,6 +18,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl';

src/backend/utils/mb/Unicode/UCS_to_GB18030.pl

@@ -14,6 +14,8 @@
 # and the "b" field is the hex byte sequence for GB18030
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_GB18030.pl';

src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl

@@ -16,6 +16,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl';

src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl

@@ -8,6 +8,8 @@
 # "sjis-0213-2004-std.txt" (http://x0213.org)
 
 use strict;
+use warnings;
+
 use convutils;
 
 # first generate UTF-8 --> SHIFT_JIS_2004 table

src/backend/utils/mb/Unicode/UCS_to_SJIS.pl

@@ -11,6 +11,8 @@
 # ftp site.
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_SJIS.pl';

src/backend/utils/mb/Unicode/UCS_to_UHC.pl

@@ -14,6 +14,8 @@
 # and the "b" field is the hex byte sequence for UHC
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_UHC.pl';

src/backend/utils/mb/Unicode/UCS_to_most.pl

@@ -16,6 +16,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_most.pl';

src/backend/utils/mb/Unicode/convutils.pm

@@ -6,6 +6,7 @@
 package convutils;
 
 use strict;
+use warnings;
 
 use Carp;
 use Exporter 'import';

src/backend/utils/sort/gen_qsort_tuple.pl

-#!/usr/bin/perl -w
+#!/usr/bin/perl
 
 #
 # gen_qsort_tuple.pl
@@ -26,6 +26,7 @@
 #
 
 use strict;
+use warnings;
 
 my $SUFFIX;
 my $EXTRAARGS;

src/bin/psql/create_help.pl

-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #################################################################
 # create_help.pl -- converts SGML docs to internal psql help
@@ -20,6 +20,7 @@
 #
 
 use strict;
+use warnings;
 
 my $docdir = $ARGV[0] or die "$0: missing required argument: docdir\n";
 my $hfile = $ARGV[1] . '.h'

src/interfaces/libpq/test/regress.pl

-#!/usr/bin/perl -w
+#!/usr/bin/perl
 
 use strict;
+use warnings;
 
 # use of SRCDIR/SUBDIR is required for supporting VPath builds
 my $srcdir = $ENV{'SRCDIR'} or die 'SRCDIR environment variable is not set';

src/pl/plperl/plc_perlboot.pl

 #  src/pl/plperl/plc_perlboot.pl
 
 use strict;
+use warnings;
 
 use 5.008001;
 use vars qw(%_SHARED $_TD);

src/pl/plperl/plperl_opmask.pl

-#!perl -w
+#!perl
 
 use strict;
 use warnings;

src/test/locale/sort-test.pl

 #! /usr/bin/perl
 
 use strict;
+use warnings;
 use locale;
 
 open(my $in_fh, '<', $ARGV[0]) || die;

src/test/perl/SimpleTee.pm

@@ -9,6 +9,7 @@
 
 package SimpleTee;
 use strict;
+use warnings;
 
 sub TIEHANDLE
 {

src/tools/fix-old-flex-code.pl

-#!/usr/bin/perl -w
+#!/usr/bin/perl
 #----------------------------------------------------------------------
 #
 # fix-old-flex-code.pl

src/tools/msvc/build.pl

@@ -3,6 +3,7 @@
 # src/tools/msvc/build.pl
 
 use strict;
+use warnings;
 
 use File::Basename;
 use File::Spec;

src/tools/msvc/pgbison.pl

@@ -3,6 +3,8 @@
 # src/tools/msvc/pgbison.pl
 
 use strict;
+use warnings;
+
 use File::Basename;
 
 # assume we are in the postgres source root

src/tools/msvc/pgflex.pl

@@ -3,6 +3,8 @@
 # src/tools/msvc/pgflex.pl
 
 use strict;
+use warnings;
+
 use File::Basename;
 
 # silence flex bleatings about file path style

src/tools/msvc/vcregress.pl

@@ -3,6 +3,7 @@
 # src/tools/msvc/vcregress.pl
 
 use strict;
+use warnings;
 
 our $config;
 

src/tools/perlcheck/perlcriticrc

@@ -19,6 +19,10 @@ verbose = %f: %m at line %l, column %c.  %e.  ([%p] Severity: %s)\n
 # allow octal constants with leading zeros
 [-ValuesAndExpressions::ProhibitLeadingZeros]
 
+# insist on use of the warnings pragma
+[TestingAndDebugging::RequireUseWarnings]
+severity = 5
+
 # for now raise severity of this to level 5
 [Subroutines::RequireFinalReturn]
 severity = 5

src/tools/pginclude/pgcheckdefines

-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #
 # This script looks for symbols that are referenced in #ifdef or defined()
@@ -21,6 +21,7 @@
 #
 
 use strict;
+use warnings;
 
 use Cwd;
 use File::Basename;

src/tools/version_stamp.pl

-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #################################################################
 # version_stamp.pl -- update version stamps throughout the source tree
@@ -21,6 +21,7 @@
 #
 
 use strict;
+use warnings;
 
 # Major version is hard-wired into the script.  We update it when we branch
 # a new development version.