Remove __PROTOBUF_PACKAGE_PREFIX

cmake/protobuf-config.cmake.in

@@ -2,12 +2,8 @@
 set(PROTOBUF_VERSION        "@protobuf_VERSION@")
 set(PROTOBUF_VERSION_STRING "@protobuf_VERSION_STRING@")
 
-# Current dir
-get_filename_component(_PROTOBUF_PACKAGE_PREFIX
-  "${CMAKE_CURRENT_LIST_FILE}" PATH)
-
 # Imported targets
-include("${_PROTOBUF_PACKAGE_PREFIX}/protobuf-targets.cmake")
+include("${CMAKE_CURRENT_LIST_DIR}/protobuf-targets.cmake")
 
 # Compute the installation prefix relative to this file.
 get_filename_component(_PROTOBUF_IMPORT_PREFIX