Use custom scripts instead of meson's gettext tooling

meson's tooling for gettext introduces a couple of issues. Firstly, it
is currently not possible [1] to specify per-language keywords. We need
this in order to ignore the 'Name' record in the desktop file.

Secondly, every invocation of 'update-po' also updates the pot file [2],
inadvertently recording the updated creation date in all translations.
Since we recommended the use of 'update-po' to translators in TRANSLATE,
this will lead to lots of unrelated changes every time a new translation
is added, even if no msgids change.

Thirdly, people who do not have meson installed are currently not able
to use the tooling it provides.

To fix these issues, this commit adds custom tooling around gettext: The
'update-pot.sh' script updates the pot and po files using xgettext(1)
and msgmerge(1), and 'init-po.sh' makes the necessary changes to LINGUAS
whilst also creating the relevant po file(s) with msginit(1).

We no longer need to refer to meson at all in TRANSLATE. Make sure to
mention the new scripts as well.

[1] https://github.com/mesonbuild/meson/issues/1739
[2] https://github.com/mesonbuild/meson/blob/a9e9b7c7501a3c8a5984a93879d1f309bf8c72aa/mesonbuild/scripts/gettext.py#L112

4 files changed, 25 insertions, 4 deletions

diff --git a/po/POTFILES b/po/POTFILES
index 107469c..4d9f89d 100644
--- a/po/POTFILES
+++ b/po/POTFILES
@@ -1,4 +1,3 @@
 configreader.vala
 terminal.ui
 terminal.vala
-weltschmerz.desktop.in
diff --git a/po/init-po.sh b/po/init-po.sh
new file mode 100644
index 0000000..0830875
--- /dev/null
+++ b/po/init-po.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+lang=$1
+
+echo "$lang" >> po/LINGUAS
+sort -u po/LINGUAS -o po/LINGUAS
+
+msginit -i po/weltschmerz.pot -o "po/${lang}.po" --locale "$lang" --no-translator
diff --git a/po/meson.build b/po/meson.build
index 5cbb15b..6870f58 100644
--- a/po/meson.build
+++ b/po/meson.build
@@ -4,6 +4,4 @@ localedir = join_paths(get_option('prefix'), get_option('localedir'))
 add_project_arguments('-DGETTEXT_PACKAGE="weltschmerz"', language: 'c')
 add_project_arguments('-DLOCALEDIR="@0@"'.format(localedir), language: 'c')
 
-i18n.gettext(meson.project_name(),
-	args: ['--directory=' + meson.source_root(), '-c TRANSLATORS', '--from-code=UTF-8']
-)
+i18n.gettext(meson.project_name(), args: '--directory=' + meson.source_root())
diff --git a/po/update-pot.sh b/po/update-pot.sh
new file mode 100644
index 0000000..6ceb21f
--- /dev/null
+++ b/po/update-pot.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+_xgettext() {
+	xgettext --package-name=weltschmerz -cTRANSLATORS "$@" -o po/weltschmerz.pot
+}
+
+_xgettext -f po/POTFILES
+
+# We treat this file specially in order to override the keywords used for it.
+# Since we do not want Name translated, reset the keyword list with -k and then
+# add the keywords we want.
+_xgettext -j -k -kComment -kKeywords weltschmerz.desktop.in
+
+while read lang; do
+	msgmerge -q -o "po/${lang}.po" "po/${lang}.po" po/weltschmerz.pot
+done < po/LINGUAS