Let clang-repl link privately against Clang components

[aaronpuchert]

Summary

First of all, this is the convention: all other tools have their
dependencies private. While it does not have an effect on linking
(there is no linking against executables), it does have an effect
on exporting: having the targets private allows installing the tools
without the libraries in a statically linked build, or a build against
libclang-cpp.so.

[v.g.vassilev]

Thanks for the clarification! LGTM!

clang/tools/clang-repl/CMakeLists.txt

 set( LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   Core
   LineEditor
   Option
   OrcJIT
   Support
   )
 
 add_clang_tool(clang-repl
   ClangRepl.cpp
   )
 
-clang_target_link_libraries(clang-repl PUBLIC
+clang_target_link_libraries(clang-repl PRIVATE
   clangBasic
   clangFrontend
   clangInterpreter
   clangTooling
   )
 
 # Support plugins.
 if(CLANG_PLUGIN_SUPPORT)
   export_executable_symbols_for_plugins(clang-repl)
 endif()