fix LD_LIBRARY_PATH for firefox.

* add dbug
* use libpng12 instead of libpng
* remove needless trailing slashes

component/firefox/buildout.cfg

@@ -34,7 +34,7 @@ script =
   wrapper = open(wrapper_location, 'w')
   wrapper.write("""#!${dash:location}/bin/dash
   cd %(location)s
-  export LD_LIBRARY_PATH=%(location)s:${libXrender:location}/lib/:${freetype:location}/lib/:${fontconfig:location}/lib/:${libX11:location}/lib/:${bzip2:location}/lib/:${libXext:location}/lib/:${libXt:location}/lib/:${zlib:location}/lib/:${libXcursor:location}/lib/:${gtk-2:location}/lib/:${cairo:location}/lib/:${pango:location}/lib/:${glib:location}/lib/:${atk:location}/lib/:${gdk-pixbuf:location}/lib/:${alsa:location}/lib/:${libpng:location}/lib/:${libSM:location}/lib/:${libICE:location}/lib:${libxml2:location}/lib:${openssl:location}/lib:${dbus-glib:location}/lib
+  export LD_LIBRARY_PATH=%(location)s:${libXrender:location}/lib:${dbus:location}/lib:${dbus-glib:location}/lib:${freetype:location}/lib:${fontconfig:location}/lib:${libX11:location}/lib:${bzip2:location}/lib:${libXext:location}/lib:${libXt:location}/lib:${zlib:location}/lib:${libXcursor:location}/lib:${gtk-2:location}/lib:${cairo:location}/lib:${pango:location}/lib:${glib:location}/lib:${atk:location}/lib:${gdk-pixbuf:location}/lib:${alsa:location}/lib:${libpng12:location}/lib:${libSM:location}/lib:${libICE:location}/lib:${libxml2:location}/lib:${openssl:location}/lib
   export PATH=${fontconfig:location}/bin:$PATH
   exec %(location)s/firefox $*""")
   wrapper.close()