klee-uclibc detection is now a lot cleaner. KLEE now assumes
it can find klee-uclibc inside the same folder as the other
runtime libraries with the name "klee-uclibc.bca"

This is implemented as follows:

* When building, a sym-link is created to klee-uclibc's libc.a file
  in the same directory that the rest of KLEE's runtime libraries
  are built. This done so that if a developer changes klee-uclibc
  on their system then the correct version of klee-uclibc is used
  by KLEE.

* When installing, klee-uclibc's libc.a file is installed in the same
  directory that the rest of KLEE's runtime libraries are installed.

In addition the configure script argument --with-uclibc can now
operate in two ways. It can either be passed the path to the root
of klee-uclibc or it can be passed a path to the libc.a file built
by klee-uclibc. This new behaviour has been added to allow users
to potential use pre-built versions of klee-uclibc.