CMake: Let LLDB build with CMake 3

Teach add_lldb_library to correctly use the CMake 2.8.12
PUBLIC/PRIVATE/INTERFACE keywords.  LLDB's CMake configuration would
inconsistently apply these keywords; this was previously a warning in
CMake 2.x but became an error in CMake 3.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@212482 91177308-0d34-0410-b5e6-96231b3b80d8
Allow specification of no source display on stop.

See http://llvm.org/bugs/show_bug.cgi?id=20149 for details.

Change by Randy Smith.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@212485 91177308-0d34-0410-b5e6-96231b3b80d8