Why doesn't GTK's configure script pay attention to PKG_CONFIG_PATH?

[skip pobox com]

I'm struggling to build gtk 2.10.6.  I have PKG_CONFIG_PATH set like so:

/opt/app/nonc++/glib-2.12/lib/pkgconfig:\
/opt/app/nonc++/freetype-2.1/lib/pkgconfig:\
/opt/app/nonc++/xrender-0.8/lib/pkgconfig:\
/opt/app/nonc++/libpng-1.2/lib/pkgconfig:\
/opt/app/nonc++/fontconfig-2.2/lib/pkgconfig:\
/opt/app/nonc++/cairo-1.2/lib/pkgconfig:\
/opt/app/nonc++/pango-1.14/lib/pkgconfig:\
/opt/app/nonc++/atk-1.9/lib/pkgconfig

and gave PKG_CONFIG on the command line to specify the path to the
pkg-config command (even though it *is* in PATH).  Still gtk's configure
spews several messages about gnome-config not being found, then barfs
when it starts looking for Pango:

>From the contents of config.log I can't see that configure made any attempt
to actually look for Pango:

    configure:30735: checking Pango flags
    configure:30747: error:
    *** Pango not found. Pango built with Cairo support is required
    *** to build GTK+. See http://www.pango.org for Pango information.

Looking in the vicinity of line 30735 I see that it executed

    /opt/app/bin/pkg-config --exists pango pangocairo

Running that manually I get

    sh: gnome-config: not found

Pango is clearly installed:

    $ ls /opt/app/nonc++/pango-1.14/lib/pkgconfig
    pango.pc   pangox.pc

as is Cairo:

    $ ls /opt/app/nonc++/cairo-1.2/lib/pkgconfig
    cairo-ft.pc            cairo-ps.pc            cairo-xlib.pc
    cairo-pdf.pc           cairo-svg.pc           cairo.pc
    cairo-png.pc           cairo-xlib-xrender.pc

What is pangocairo?  I can't find a package by that name searching via
Google or poking around on gtk.org, cairo.org or pango.org.

I successfully built glib, pango and cairo earlier this afternoon.  What's
wrong with gtk (or with me)?

Here are my relevant environment variable settings:

    CPPFLAGS=-I/opt/app/nonc++/glib-2.12/include -I/opt/app/nonc++/xrender-0.8/include -I/opt/app/nonc++/pango-1.14/include
    LD_LIBRARY_PATH=/opt/app/nonc++/glib-2.12/lib:/opt/app/nonc++/xrender-0.8/lib:/opt/app/nonc++/pango-1.14/lib
    PATH=/home/titan/skipm/local/bin:/opt/tradelink/research/python/scripts:/opt/tradelink/research/share/scripts:/opt/app/g++lib6/python-2.4/bin:/opt/app/g++lib6/gcc-3.4/bin:/opt/app/bin:/opt/lang/bin:/opt/app/sybase-12.5.1/OCS-12_5/bin:/opt/tradelink/bin:/opt/tradelink/share/scripts:/usr/X11R6/bin:/usr/X/bin:/opt/gnome2/2.2/bin:/opt/local/bin:/usr/bin:/bin:/usr/ccs/bin:/usr/ucb
    LD_RUN_PATH=/opt/app/nonc++/glib-2.12/lib:/opt/app/nonc++/xrender-0.8/lib:/opt/app/nonc++/pango-1.14/lib
    PKG_CONFIG_PATH=/opt/app/nonc++/glib-2.12/lib/pkgconfig:/opt/app/nonc++/freetype-2.1/lib/pkgconfig:/opt/app/nonc++/xrender-0.8/lib/pkgconfig:/opt/app/nonc++/libpng-1.2/lib/pkgconfig:/opt/app/nonc++/fontconfig-2.2/lib/pkgconfig:/opt/app/nonc++/cairo-1.2/lib/pkgconfig:/opt/app/nonc++/pango-1.14/lib/pkgconfig:/opt/app/nonc++/atk-1.9/lib/pkgconfig

and my configure command:

    PKG_CONFIG=/opt/app/bin/pkg-config ./configure CC=/opt/app/g++lib6/gcc-3.4/bin/gcc --prefix=/opt/app/nonc++/gtk+-2.10

All the LD_LIBRARY_PATH, LD_RUN_PATH, PKG_CONFIG and CPPFLAGS hair was
necessary to get past earlier problems in the gtk configure process.

Environment is GCC 3.4 on Solaris 10, obviously trying to avoid Sun's
libraries and include files.

Thx,

-- 
Skip Montanaro - skip pobox com - http://www.mojam.com/
"The hippies and the hipsters did some great stuff in the sixties,
but the geeks pulled their weight too." -- Billy Bragg