fix: make running from code tree translate strings

Have Roundup's i18n add working_directorylocale/locale to the list of
places searched for translation .mo files.

This means:

  LANG=de python3 roundup/scripts/roundup_admin.py -i ...

will be translated to German. Also document setting up locale/locale
using 'make -C locale local_install' in developer doc.

Author: rouilj

doc/developers.txt

@@ -119,6 +119,20 @@ sqlite`` and get a working Roundup server. This will start
 the server using the ``sqlite`` backend. The code is in the
 ``roundup`` subdirectory.
 
+To test internationalization in your environment, you have to
+process the locale sub-directory into a form that roundup's
+i18n code will recognize. To do this use:
+
+  make -C locale local_install
+
+which will compile the ``.po`` source files into binary
+``.mo`` files and install them under
+``locale/locale/<LANGUAGE_CODE>/LC_MESSAGES/roundup.mo``. For
+German this will be
+``locale/locale/de/LC_MESSAGES/roundup.mo``.  You will need
+``msgfmt`` from the the GNU gettext tools to be installed on
+your system.
+
 Submitting Changes
 ------------------
 

roundup/i18n.py

@@ -67,23 +67,32 @@
 # os.prefix should be /usr, /usr/local or root of virtualenv
 #    strip leading / to make os.path.join work right.
 path = __file__
-for _N in 1, 2:
+
+for _N in 1, 2:  # remove roundup/i18n.py from path
     path = os.path.dirname(path)
     # path is /usr/local/lib/python3.10/site-packages
+
 _ldir = os.path.join(path, sys.prefix[root_prefix_chars:], 'share', 'locale')
 if os.path.isdir(_ldir):
     LOCALE_DIRS.append(_ldir)
+
 # try other places locale files are hidden on install
 _ldir = os.path.join(path, sys.prefix[root_prefix_chars:], 'local', 'share', 'locale')
 if os.path.isdir(_ldir):
     LOCALE_DIRS.append(_ldir)
+
 try:
     _ldir = os.path.join(path, sys.base_prefix[root_prefix_chars:], 'local', 'share', 'locale')
     if os.path.isdir(_ldir):
         LOCALE_DIRS.append(_ldir)
     _ldir = os.path.join(path, sys.base_prefix[root_prefix_chars:], 'share', 'locale')
     if os.path.isdir(_ldir):
         LOCALE_DIRS.append(_ldir)
+
+    # make -C locale local_install - locale directory in roundup source tree
+    _ldir = os.path.join(path, 'locale', 'locale')
+    if os.path.isdir(_ldir):
+        LOCALE_DIRS.append(_ldir)
 except AttributeError:
     pass  # no base_prefix on 2.7
 del _ldir