Integrate desktop file translation into meson

meson’s i18n module get’s confused by .template and fails
to extract translatable strings, thus rename to in.in.

Note: while this slightly improves the situation, meson’s aegisub-pot
target is still missing many strings. make_pot.sh should be used.

packages/meson.build

@@ -18,8 +18,8 @@ elif host_machine.system() == 'darwin'
 else
     conf_pkg.set('AEGISUB_COMMAND', 'aegisub')
 
-    desktop_template = configure_file(input: 'desktop/aegisub.desktop.template.in',
-                                      output: 'aegisub.desktop.template',
+    desktop_template = configure_file(input: 'desktop/aegisub.desktop.in.in',
+                                      output: 'aegisub.desktop.in',
                                       configuration: conf_pkg)
 
     i18n = import('i18n')

po/POTFILES

@@ -1,3 +1,5 @@
+packages/desktop/aegisub.desktop.in.in
+
 src/ass_style.cpp
 src/audio_box.cpp
 src/audio_karaoke.cpp

po/make_pot.sh

@@ -41,7 +41,7 @@ find ../automation -name *.lua \
 
 for i in 'Name' 'GenericName' 'Comment' 'Keywords'
 do
-  grep ^$i -n ../packages/desktop/aegisub.desktop.template.in \
+  grep ^$i -n ../packages/desktop/aegisub.desktop.in.in \
     | sed 's/\([0-9]\+\):[^=]\+=\(.*\)$/aegisub.desktop|\1|"\2"/' \
     | maybe_append
 done