To build and install the uClibc development environment,
1) cp ./extra/Configs/Config. ./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.