To build and install the uClibc development environment,

1) cp ./extra/Configs/Config.<your arch> ./Config
2) Edit ./Config for your setup.
3) make
4) make install_dev (as root if necessary, depending on your Config)


To install the runtime environment,
   make install_target  (again, as root if necessary)

To compile programs with uClibc,

   export PATH={uClibc DEVEL_PREFIX/ROOT_DIR}/bin:$PATH

and then just ./configure and make as usual.

Note: You may also want to look at extra/gcc-uclibc/gcc-uclibc.c for
      additional information concerning what options and environment
      variables the gcc wrapper handles.