[lldb] Enable building with Cmake/BUILD_SHARED_LIBS

Summary:
Several changes to fix CMake builds of LLDB with the
BUILD_SHARED_LIBS setting on.

- Force all internal libraries to be built STATIC.
- Add additional library dependencies (pthread, dl,
  runtimedyld).
- modify finalisation of SWIG wrapper to symlink the
  "lib" dir into python/site-packages, so _lldb.so's
  RPATH resolves.

Test Plan: Verified one test case with "dotest.py".

Reviewers: sylvestre.ledru, zturner

Reviewed By: zturner

Subscribers: zturner, ted, tberghammer, emaste, lldb-commits

Differential Revision: http://reviews.llvm.org/D10157

llvm-svn: 239007