diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8aeb183..42c421b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -46,6 +46,7 @@ CONFIGURE_FILE(
 
 # define include directories
 INCLUDE_DIRECTORIES(
+    ${CMAKE_SOURCE_DIR}
     ${CMAKE_SOURCE_DIR}/include
     ${CMAKE_BINARY_DIR}/include
 )