KLEE: build klee-uclibc
KLEE: build klee-uclibc

This builds the klee-uclibc library recommended by the KLEE devs.
This will make it easier to work on issues with this library so
that we can make it the default choice sometime in the future.

project-oak/rust-verification-tools,project-oak/rust-verification-tools,project-oak/rust-verification-tools,project-oak/rust-verification-tools