What am I missing in Firefox? (was: Re: Yelp 2.23.91 released

[tjoen <tjoen dds nl>]

2.23.91 configured with:
CPPFLAGS=-DXPCOM_GLUE \
./configure --prefix=/usr --disable-static

$ yelp
Could not initialize gecko!

Am I missing something in Firefox?
System is built from sources. Gnome 2.22.2.

Firefox 3.0.1 is configured this way:
cat > .mozconfig <<EOF
mk_add_options MOZ_OBJDIR= TOPSRCDIR@/objdir
. \$topsrcdir/browser/config/mozconfig
ac_add_options --prefix=/usr
ac_add_options --with-system-jpeg
ac_add_options --with-system-zlib
ac_add_options --enable-default-toolkit=cairo-gtk2
ac_add_options --disable-freetype2
ac_add_options --enable-xft
ac_add_options --disable-installer
ac_add_options --enable-system-sqlite
ac_add_options --enable-system-cairo
EOF

%install
make DESTDIR=$RPM_BUILD_ROOT install
install nsprpub/config/nspr-config $RPM_BUILD_ROOT/usr/bin/
install objdir/dist/bin/xpidl $RPM_BUILD_ROOT/usr/bin/
install objdir/dist/bin/xpt_link $RPM_BUILD_ROOT/usr/bin/
mkdir $RPM_BUILD_ROOT/usr/include/firefox-%version/nss
cp dist/public/nss/* $RPM_BUILD_ROOT/usr/include/firefox-%version/nss/
cd $RPM_BUILD_ROOT/
install /usr/bin/nss-config usr/bin/

This is /usr/bin/nss-config:
#!/bin/sh
prefix=/usr
exec_prefix=/usr
libdir=/usr/lib/firefox-devel-3.0.1/sdk/lib
includedir=/usr/include/firefox-3.0.1
Libs="-L${libdir} -lnss3 -lnssutil3 -lsmime3 -lssl3 -lsoftokn3 -lxul"
Cflags="-I${includedir}/nss"
major_version=3
minor_version=12
patch_version=0
[etc]

ln -s firefox-%version/stable/ usr/include/nspr
mv usr/lib/firefox-%version usr/lib/mozilla
ln -s mozilla usr/lib/firefox-%version
(cd usr/lib/mozilla/; for i in *.so; do ln -s mozilla/$i ../$i; done)
install -D -m 644 /usr/lib/pkgconfig/firefox-plugin.pc \
	usr/lib/pkgconfig/firefox-plugin.pc
install -D -m 644 /usr/lib/pkgconfig/firefox-xpcom.pc \
        usr/lib/pkgconfig/firefox-xpcom.pc

This is /usr/lib/pkgconfig/firefox-xpcom.pc:
prefix=/usr
exec_prefix=/usr
libdir=/usr/lib/firefox-devel-3.0.1/sdk/lib
includedir=/usr/include/firefox-3.0.1/unstable
idldir=/usr/share/idl/firefox-3.0.1/stable
Name: XPCOM
Description: The Mozilla Cross Platform Component Library
Version: 3.0.1
Libs: -L${libdir} -lxpcom
Cflags: -I/usr/include/firefox-3.0.1/stable -I${includedir}