diff --git a/demo/CMakeLists.txt b/demo/CMakeLists.txt
--- a/demo/CMakeLists.txt
+++ b/demo/CMakeLists.txt
@@ -1,7 +1,6 @@
 INCLUDE_DIRECTORIES(
   ${CMAKE_SOURCE_DIR}
   ${CMAKE_BINARY_DIR}
-  ${GLPK_INCLUDE_DIR}
 )
 
 LINK_DIRECTORIES(${CMAKE_BINARY_DIR}/lemon)