Change libbcc so that it compiles as an LLVM loadable module.

The main change is not requiring libLLVM in the makefile for libbcc.
With this change, libbcc can be used as an LLVM loadable module, for
instance as in "opt -load". This is helpful for debugging
individual bcc passes.

Change-Id: I6565694738c85baac7282a8dd24604f3d94cf783
2 files changed