[PATCH] tmpfile: modernize to 5.10.1+, note O_APPEND workaround

[Eric Wong <e@80x24.org>]

Once again we'll need O_APPEND on a temporary file, so note we
support it, here; since Perl 5.32 is way too new to depend on
our users having.
---
 Just something I noticed while working on other stuff, since
 I'll be relying on O_APPEND tmpfile behavior in yet another place.

 lib/PublicInbox/Tmpfile.pm | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/Tmpfile.pm b/lib/PublicInbox/Tmpfile.pm
index 25bb3a52..eb0fce00 100644
--- a/lib/PublicInbox/Tmpfile.pm
+++ b/lib/PublicInbox/Tmpfile.pm
@@ -2,8 +2,8 @@
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 package PublicInbox::Tmpfile;
 use strict;
-use warnings;
-use base qw(Exporter);
+use v5.10.1;
+use parent qw(Exporter);
 our @EXPORT = qw(tmpfile);
 use Fcntl qw(:DEFAULT);
 use Errno qw(EEXIST);
@@ -13,6 +13,9 @@ use File::Spec;
 # unlinked filename which makes sense when viewed with lsof
 # (at least on Linux)
 # And if we ever stop caring to have debuggable filenames, O_TMPFILE :)
+#
+# This is also for Perl <5.32 which lacks: open(..., '+>>', undef)
+# <https://rt.perl.org/Ticket/Display.html?id=134221>
 sub tmpfile ($;$$) {
 	my ($id, $sock, $append) = @_;
 	if (defined $sock) {