[CMake] Use correct visibility for linked libraries in CMake

When linking library dependencies, we shouldn't need to export linked
libraries to dependents. We should be explicit about this in
target_link_libraries, otherwise other targets that depend on these such
as sanitizers get repeated (and possibly even conflicting) dependencies.

Differential Revision: https://reviews.llvm.org/D57456

llvm-svn: 352654
GitOrigin-RevId: b9128d8def879775838876af43592da01ecbc18d
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 24489e8..79ea8d9 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -241,7 +241,7 @@
   if(COMMAND llvm_setup_rpath)
     llvm_setup_rpath(cxx_shared)
   endif()
-  target_link_libraries(cxx_shared ${LIBCXX_LIBRARIES})
+  target_link_libraries(cxx_shared PRIVATE ${LIBCXX_LIBRARIES})
   set_target_properties(cxx_shared
     PROPERTIES
       LINK_FLAGS    "${LIBCXX_LINK_FLAGS}"
@@ -265,7 +265,7 @@
 # Build the static library.
 if (LIBCXX_ENABLE_STATIC)
   add_library(cxx_static STATIC ${cxx_static_sources})
-  target_link_libraries(cxx_static ${LIBCXX_LIBRARIES})
+  target_link_libraries(cxx_static PRIVATE ${LIBCXX_LIBRARIES})
   set(CMAKE_STATIC_LIBRARY_PREFIX "lib")
   set_target_properties(cxx_static
     PROPERTIES