NMT:cross

export CTARGET=mipsel-linux-uclibc
export ARCH=mips

rm -rf build
mkdir build
cd build
../binutils-2.17/configure \
	--target=$CTARGET \
	--prefix=/usr/local/$ARCH/ \
	--with-sysroot=/usr/local/$ARCH/$CTARGET \
	--disable-werror
make
make install

# It installs things we don't want (and will fail later)
rm -rf /usr/local/$ARCH/{info,lib,man,share}

export PATH=/usr/local/$ARCH/bin:$PATH


cd ../linux-2.6.15.7
yes "" | make ARCH=$ARCH oldconfig prepare

#With 2.6.x, this will probably end in an error because you don't have a gcc 
#cross-compiler yet, but you can ignore that.  Just copy over the headers:

mkdir -p /usr/local/$ARCH/$CTARGET/usr/include/
rsync -arv include/linux include/asm-generic /usr/local/$ARCH/$CTARGET/usr/include/
rsync -arv include/asm-$ARCH/ /usr/local/$ARCH/$CTARGET/usr/include/asm
 
cd ../uClibc-0.9.28.3/

make menuconfig
#Target Architecture: mips
#Target Architecture Features and Options: 
#  Target Process Architecture: MIPS I
#  Target Process Endianness: Little Endian
#  Target CPU has a memory management unit (MMU): YES
#  Enable floating point number support: YES
#  Target CPU has a floating point unit: NO
#  (/usr/local/mips/mipsel-linux-uclibc/usr) Linux kernel header location
#
#Library Installation Options
#  (/usr/local/mips/mipsel-linux-uclibc) uClibc runtime library directory
#  (/usr/local/mips/mipsel-linux-uclibc/usr) uClibc development environment
#
#uClibc development/debugging options
#  (mipsel-linux-uclibc-) Cross-compiling toolchain prefix

# This command should fail.
make CROSS=mipsel-linux-uclibc-  

# Copy the new include files
rsync -arvL include/ /usr/local/$ARCH/$CTARGET/sys-include


cd ../build/
rm -rf *

../gcc-4.0.4/configure \
	--target=$CTARGET \
	--prefix=/usr/local/mips \
	--with-sysroot=/usr/local/mips/$CTARGET \
	--enable-languages=c \
	--disable-shared \
	--disable-checking \
	--disable-werror \
       --disable-__cxa_atexit \
       --enable-target-optspace \
       --disable-nls \
       --enable-multilib \
       --with-float=soft \
       --enable-sjlj-exceptions \
       --disable-threads

make
make install

# Remove the temporary headers, and compile it properly.
rm -rf /usr/local/$ARCH/$CTARGET/sys-include


cd ../uClibc-0.9.28.3/

make CROSS=mipsel-linux-uclibc-
make install

# This bit fixes the C++ issue. But should not be required. TODO: Figure out why
cd /usr/local/mips/$CTARGET/lib
ln -s ../usr/lib//crti.o .
ln -s ../usr/lib//crtn.o .
ln -s ../usr/lib//crt1.o .

# Now recompile gcc fully.
cd ../build/
rm -rf *
../gcc-4.0.4/configure \
       --target=$CTARGET \
       --prefix=/usr/local/mips \
       --with-sysroot=/usr/local/mips/$CTARGET \
       --enable-languages=c,c++ \
       --enable-shared \
       --disable-checking \
       --disable-werror \
       --disable-__cxa_atexit \
       --enable-target-optspace \
       --disable-nls \
       --enable-multilib \
       --with-float=soft \
       --enable-sjlj-exceptions \
       --enable-threads=posix


# It is likely it will fail on __ctype_touplow_t*, this is quite easy to fix.
# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14939
# I went with the #ifdef changes of ../gcc-4.0.4/libstdc++-v3/config/locale/generic/c_locale.h
# and ../gcc-4.0.4/libstdc++-v3/config/os/gnu-linux/ctype_base.h 

make 
make install

Unfortunately this will use libc dynamic linker, which is incorrect. So at the moment, use the following line to compile your executables.

# gcc -Wl,--dynamic-linker,/lib/ld-uClibc.so.0 -o hello hello.c

I will attempt to find out how to make it use the correct dynamic linker by default.

Thanks to emveepee we now know to do this:

1. To get around the need to specify the dynamic-linker I found you could be able to modify the default 
dynamic-linker in gcc4.0.4/gcc/config/mips/linux.h

I just modified line 118 to the proper setting rather than applying the patch discussed in the following
url and the problem goes away.

http://www.busybox.net/lists/uclibc/2004-January/007943.html

2. The soft floating-point functions will not be linked in by default without a patch
http://bugs.busybox.net/view.php?id=1069 which I haven't tried yet but linking in -lgcc_s also
solves the problem.