Why exactly is the Glib::ustring::compose() feature blocking this?

There is a standalone version if it's really needed. It's just a header:
http://people.iola.dk/olau/compose/

Initial translatability has been implemented with these commits:

commit 2db3224a2d7e0f9101240fa381699075b4baf46b
Author: herzi <herzi@910bfebc-b532-0410-a802-fb3981afa09c>
Date:   Wed Apr 8 19:25:16 2009 +0000

    improved the main window translatability
    
    * po/POTFILES.in: new translatable files
    * po/de.po: updated German translation
    * src/pptout/window.cc,
    * src7pptout/windowmenus.cc: added more translatable strings
    
    
    git-svn-id: svn+ssh://svn.gnome.org/svn/passepartout/trunk@1534 910bfebc-b532-0410-a802-fb3981afa09c

commit b39735e3029fa8d53b1898d3033056b8d3699ff5
Author: herzi <herzi@910bfebc-b532-0410-a802-fb3981afa09c>
Date:   Wed Apr 8 19:25:04 2009 +0000

    started translatability
    
    * autogen.sh: fixed support for srcdir!=builddir invocations
    * configure.ac: added intltool and glib-gettext dependencies; depend on glibmm
      2.16 for Glib::ustring::compose()
    * Makefile.am: added passepartout.desktop to the installed files
    * passepartout.desktop -> passepartout.desktop.in: renamed and changed for
      translatability
    * po/LINGUAS: added a list of German and Swedish
    * po/POTFILES.in: added some files to be translated
    * po/de.po: initial German translation
    * po/sv.po: initial Swedish translation (with the one message from the .desktop
      file)
    * src/pptout/main.cc: made the help messages translatable
    
    
    git-svn-id: svn+ssh://svn.gnome.org/svn/passepartout/trunk@1533 910bfebc-b532-0410-a802-fb3981afa09c

Adding keywords, we'll close this bug once we think there are enough translatable strings.

This should be finished now:

http://git.gnome.org/cgit/passepartout/commit/?id=50b94bbc4ad49265151244099a064e1e358a1e0b

Closing per comment 4