build: build all dependencies in parallel (#22329)

Previously, all targets were connected in one main target called
third-party in order to remove any potentially conflicting shared
library. We can make each dependency target independent of each other by
only removing shared libraries from luajit and msgpack in their own
targets, as only these has unwanted shared libraries.

cmake.deps/cmake/BuildMsgpack.cmake

@@ -11,4 +11,10 @@ ExternalProject_Add(msgpack
     -D MSGPACK_BUILD_EXAMPLES=OFF
   CMAKE_CACHE_ARGS ${DEPS_CMAKE_CACHE_ARGS})
 
-list(APPEND THIRD_PARTY_DEPS msgpack)
+if (NOT MSVC)
+  add_custom_target(clean_shared_libraries_msgpack ALL
+    COMMAND ${CMAKE_COMMAND}
+      -D REMOVE_FILE_GLOB=${DEPS_INSTALL_DIR}/lib/${CMAKE_SHARED_LIBRARY_PREFIX}*${CMAKE_SHARED_LIBRARY_SUFFIX}*
+      -P ${PROJECT_SOURCE_DIR}/cmake/RemoveFiles.cmake)
+  add_dependencies(clean_shared_libraries_msgpack msgpack)
+endif()