trouble building with included libraries

[Sam Hansen]

I am attempting to compile gcc, configured as a cross compiler.  I
explicitly do not have libgmp, libmpfr, or libmpc installed on my
system.  The documentation at http://gcc.gnu.org/wiki/InstallingGCC
indicates that I may compile these libraries as part of the gcc
compilation process overall.

To cut a long story short:

$ tar -xjf gcc-4.8.2.tar.bz2
$ mkdir objdir
$ cd gcc-4.8.2/
$ contrib/download_prerequisites
...
[sources downloaded, extracted, symlinks created]
...
$ cd ../objdir/
$ ../gcc-4.8.2/configure \
  --target=avr \
  --enable-languages=c \
  --prefix=/home/sam/local
...
$ make
...
[compilation proceeds for a while]
...
configure: error: cannot compute suffix of object files: cannot compile
See `config.log' for more details.
make[1]: *** [configure-target-libgcc] Error 1
make[1]: Leaving directory `/home/sam/objdir'
make: *** [all] Error 2

The error is logged in objdir/avr/libgcc/config.log.  I understand
this indicates that the prerequisite libraries weren't set up
correctly prior to the compilation?  Further, no compiled libraries
(static or dynamic) seem to be present in objdir/.

Why do the dependent libraries not seem to be compiled as per the
above wiki document?  Was there a configure script flag I needed to
pass to tell the compiler to also compile the dependent libraries?

Thanks for any insight you might have.