i18n: Extract messages from all installed plugins.

This makes "make i18n" extract messages for translation from all
installed plugins as well.

r2/Makefile

@@ -71,7 +71,7 @@ GENERATED_STRINGS_FILE := r2/lib/generated_strings.py
 
 # POTFILE is set by Makefile.py
 i18n: $(GENERATED_STRINGS_FILE)
-	$(PYTHON) setup.py extract_messages -o $(POTFILE)
+	$(PYTHON) setup.py extract_messages --input-dirs=r2,$(PLUGIN_I18N_PATHS) -o $(POTFILE)
 
 $(GENERATED_STRINGS_FILE): $(STRINGS_FILE)
 	paster run standalone $(STRINGS_FILE) -c "generate_strings()" > $(GENERATED_STRINGS_FILE)

r2/Makefile.py

@@ -30,6 +30,11 @@ print 'POTFILE := ' + os.path.join(I18N_PATH, 'r2.pot')
 plugins = PluginLoader()
 print 'PLUGINS := ' + ' '.join(plugin.name for plugin in plugins
                                if plugin.needs_static_build)
+
+print 'PLUGIN_I18N_PATHS := ' + ','.join(os.path.relpath(plugin.path)
+                                         for plugin in plugins
+                                         if plugin.needs_translation)
+
 import sys
 for plugin in plugins:
     print 'PLUGIN_PATH_%s := %s' % (plugin.name, plugin.path)

r2/r2/lib/plugin.py

@@ -34,6 +34,7 @@ class Plugin(object):
     config = {}
     live_config = {}
     needs_static_build = False
+    needs_translation = True
     errors = {}
 
     def __init__(self, entry_point):