Someone

make -C rt2x00 compile
Forcing package rebuild
Rebuilding /home/mj/tmp/trunk2/trunk/bin/packages/kmod-rt2x00_2.6.19.2+20061230-brcm-1_mipsel.ipk
make[4]: Entering directory `/home/mj/tmp/trunk2/trunk/package/rt2x00'
rm -f /home/mj/tmp/trunk2/trunk/staging_dir_mipsel/stampfiles/.kmod-rt2x00-installed
mkdir -p /home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00
cp -fpR ./src/* /home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00/
touch /home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00/.prepared
(cd /home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00/; if [ -x configure ]; then AR=mipsel-linux-uclibc-ar AS="mipsel-linux-uclibc-gcc -c -Os -pipe -mips32 -mtune=mips32 -funit-at-a-time" LD=mipsel-linux-uclibc-ld NM=mipsel-linux-uclibc-nm CC="mipsel-linux-uclibc-gcc" GCC="mipsel-linux-uclibc-gcc" CXX=mipsel-linux-uclibc-g++ RANLIB=mipsel-linux-uclibc-ranlib STRIP=mipsel-linux-uclibc-strip OBJCOPY=mipsel-linux-uclibc-objcopy CFLAGS="-Os -pipe -mips32 -mtune=mips32 -funit-at-a-time" CXXFLAGS="-Os -pipe -mips32 -mtune=mips32 -funit-at-a-time" CPPFLAGS="-I/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/usr/include -I/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/include" LDFLAGS="-L/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/usr/lib -L/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/lib" PKG_CONFIG_PATH="/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/usr/lib/pkgconfig" PKG_CONFIG_LIBDIR="/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/usr/lib/pkgconfig"  ./configure --target=mipsel-linux --host=mipsel-linux --build=i686-pc-linux-gnu --program-prefix="" --program-suffix="" --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --libexecdir=/usr/lib --sysconfdir=/etc --datadir=/usr/share --localstatedir=/var --mandir=/usr/man --infodir=/usr/info --disable-nls ; fi; )
touch /home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00/.configured
make -C "/home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00" CROSS_COMPILE="mipsel-linux-uclibc-" ARCH="mips" EXTRA_CFLAGS="-I/home/mj/tmp/trunk2/trunk/staging_dir_mipsel/usr/include" modules
make[5]: Entering directory `/home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00'
make[5]: *** No rule to make target `modules'.  Stop.
make[5]: Leaving directory `/home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00'
make[4]: *** [/home/mj/tmp/trunk2/trunk/build_mipsel/linux-2.6-brcm/kmod-rt2x00/.built] Error 2
make[4]: Leaving directory `/home/mj/tmp/trunk2/trunk/package/rt2x00'
make[3]: *** [rt2x00-compile] Error 2
make[3]: Leaving directory `/home/mj/tmp/trunk2/trunk/package'
make[2]: *** [compile] Error 2
make[2]: Leaving directory `/home/mj/tmp/trunk2/trunk/package'
make[1]: *** [package/compile] Error 2
make[1]: Leaving directory `/home/mj/tmp/trunk2/trunk'
make: *** [world] Error 2

changed in the Makefile the compile section to:

define Build/Compile
        $(MAKE) -C "$(PKG_BUILD_DIR)" \
                CROSS_COMPILE="$(TARGET_CROSS)" \
                ARCH="$(LINUX_KARCH)" \
                EXTRA_CFLAGS="-I$(STAGING_DIR)/usr/include" \
                modules