Purpose: avoid this cmake error:
    CMake Error at cmake/ConfigGen.cmake:95 (list):
      list sub-command REMOVE_ITEM requires two or more arguments.
    Call Stack (most recent call first):
      CMakeLists.txt:93 (caffe_generate_export_configs)
Forward: not yet.
--- a/cmake/ConfigGen.cmake
+++ b/cmake/ConfigGen.cmake
@@ -92,7 +92,7 @@
   # remove source and build dir includes
   caffe_get_items_with_prefix(${PROJECT_SOURCE_DIR} Caffe_INCLUDE_DIRS __insource)
   caffe_get_items_with_prefix(${PROJECT_BINARY_DIR} Caffe_INCLUDE_DIRS __inbinary)
-  list(REMOVE_ITEM Caffe_INCLUDE_DIRS ${__insource} ${__inbinary})
+  list(REMOVE_ITEM Caffe_INCLUDE_DIRS ${__insource} ${__inbinary} "")
 
   # add `install` include folder
   set(lines
