po4a: fix build with gettext 0.22

Using patch from upstream bug tracker

textproc/po4a/distinfo

@@ -1,10 +1,11 @@
-$NetBSD: distinfo,v 1.28 2023/06/21 19:08:06 schmonz Exp $
+$NetBSD: distinfo,v 1.29 2023/07/03 21:16:53 wiz Exp $
 
 BLAKE2s (po4a-0.69.tar.gz) = c82a56664a6a9a674b02f1026843d65aea6671c913738f6e1e565d7242dbe96d
 SHA512 (po4a-0.69.tar.gz) = 9cb5eec547ab18d1c3ebdda212b909fc4f5489a74641ba2d7e0a3a1d060f245d23667c16e687c678c5ccc3809c9315d20673266dcc3764172a899caa397238e3
 Size (po4a-0.69.tar.gz) = 4665710 bytes
 SHA1 (patch-Po4aBuilder.pm) = b5a3dae1f53c56e78dbc1034f6313cbede00ce3a
 SHA1 (patch-lib_Locale_Po4a_Po.pm) = 481171dc8f7cbceb0d532f8d3074750d2de82b10
+SHA1 (patch-lib_Locale_Po4a_Sgml.pm) = 3179dd9c39ce8bc346ca6b4ec7bb9ea9a399eb1b
 SHA1 (patch-lib_Locale_Po4a_Text.pm) = d019287e6c03671da4433689691b5447a665208e
 SHA1 (patch-msguntypot) = 299b1ee02dfce836980eee3b7d5ae23256b66cd8
 SHA1 (patch-po4a) = 114b1ea9247bdcc17ed125c19d57d10fb3bca805

textproc/po4a/patches/patch-lib_Locale_Po4a_Sgml.pm

@@ -0,0 +1,16 @@
+$NetBSD: patch-lib_Locale_Po4a_Sgml.pm,v 1.1 2023/07/03 21:16:53 wiz Exp $
+
+Fix build with gettext 0.22
+https://github.com/jpalus/po4a/commit/9f102bba1b279294de637ad5ec93c64cf7da70e7
+
+--- lib/Locale/Po4a/Sgml.pm.orig	2023-07-03 21:10:46.730796044 +0000
++++ lib/Locale/Po4a/Sgml.pm
+@@ -773,7 +773,7 @@ sub parse_file {
+             while ( $origfile =~ /^(.*?)&$key(;.*$|[^-_:.A-Za-z0-9].*$|$)/s ) {
+ 
+                 # Since we will include a new file, we
+-                # must do a new round of substitutions.
++                # must do a new round of substitutions.
+                 $dosubstitution = 1;
+                 my ( $begin, $end ) = ( $1, $2 );
+                 $end = "" unless ( defined $end );