[CMake] Accept entitlements for code signing in add_lldb_library()
D57334 added entitlements support in add_llvm_library() so we can use it for library targets in LLDB.
Additionally this patch fixes the way that the entitlements argument is passed on from add_lldb_executable() to add_llvm_executable(). We still need the explicit parsing and passing on of single- and multi-value arguments as long as we are on CMake < 3.7 (due to bug https://gitlab.kitware.com/cmake/cmake/merge_requests/133).
Reviewers: beanz, JDevlieghere, aprantl
Reviewed By: JDevlieghere
Subscribers: mgorny, lldb-commits, #lldb
Differential Revision: https://reviews.llvm.org/D57378