meson: add po support

meson.build

@@ -199,3 +199,4 @@ foreach g : gopt
 endforeach
 
 subdir('unitTests')
+subdir('po')

po/meson.build

@@ -0,0 +1,16 @@
+gtext = find_program('xgettext', required: get_option('nls'))
+if not gtext.found()
+  subdir_done()
+endif
+
+i18n = import('i18n')
+
+i18n.gettext(
+  'exiv2',
+  preset: 'glib',
+  args: [
+    '--files-from=@0@/POTFILES.in'.format(meson.current_source_dir()),
+    '--copyright-holder="Exiv2 authors"',
+    '--msgid-bugs-address=https://github.com/Exiv2/exiv2/issues',
+  ],
+)