Appended is a patch that adds simple glibc multilib capability.

 scripts/build/libc/glibc-eglibc.sh-common
  main part: do_libc_backend_multilib():
   calls "do_libc_backend" multilib-times with 2 options
   extra_dir="/${dir}" extra_flags="${flags}"
   at the end do_libc_backend_rearrange is called to rearange
   the sysroot directories.
 config/cc/gcc.in.2
   Add CC_MULTILIB option
 patches/gcc/4.6.0/200-sparc-leon.patch
   Multilibbed sparc-leon compile. The multilibbed gcc is
   compiled with Vendor set to "leon3"
 patches/glibc/2.14/400-sparc-leon.patch
   Some fixes to get glibc-2.14 compiled with soft-float
 patches/glibc/2.14/401-s_fma_f.patch
   Some fixes to get glibc-2.14 compiled with soft-float
 scripts/build/binutils/binutils.sh
   add multilib
 scripts/build/cc/gcc.sh
   add multilib

-- Konrad