Complex Text Rendering in Mozilla

[Peter Jeremy]

I'm trying to get mozilla to render Devanagari (Hindi) text and
whilst the correct glyphs are displayed (so the correct font is
found), the vowel/consonant ordering is wrong (which indicates
that the complex text rendering isn't working).  For an example
of the problem, see
http://en.wikipedia.org/wiki/Wikipedia:Enabling_complex_text_support_for_Indic_scripts#Check_for_existing_support

I've checked and --enable-ctl is defined and the appropriate shared
libraries are built and installed.  But looking at the access times,
they are never loaded:
-r-xr-xr-x  1 root  wheel   25144 Apr 16 09:16 components/libctl.so
-rwxr-xr-x  1 root  wheel   96584 Apr 16 17:57 libmoz_art_lgpl.so
-rwxr-xr-x  1 root  wheel  603680 Apr 16 17:57 libmozjs.so
-rwxr-xr-x  1 root  wheel   25344 Apr 16 09:16 libmozpango-dvngx.so (*)
-rwxr-xr-x  1 root  wheel   12544 Apr 16 09:16 libmozpango-thaix.so
-rwxr-xr-x  1 root  wheel   25080 Apr 16 09:16 libmozpango.so
-rw-r--r--  1 root  wheel     245 Apr 16 09:16 pango.modules
(*) is the devanagari rendering module.

Googling the problem suggests that either:
1) I need to use MOZ_ENABLE_PANGO in the environment.
   This has no effect and I can't find any reference to this environment
   variable in the mozilla source code or any dependencies.
2) It should work automatically (which it doesn't for me)

My reading of the code suggests that libctl should load libmozpango
which reads pango.modules and then loads both libmozpango-dvngx.so and
libmozpango-thaix.so - but I'm not sure how to get libctl to load.

I'm running 6.1-RC1 with a newly upgraded ports tree but I had
previously tried in January with the same results.

Can anyone help?

-- 
Peter Jeremy