build BUGFIX use current vars
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 463cb23..e2a0c92 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,14 +5,14 @@
 endif()
 
 # force out-of-source build
-if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})
+if(${CMAKE_CURRENT_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_BINARY_DIR})
     message(FATAL_ERROR "In-source build is not allowed. Please make a standalone build directory and run CMake from there. You may need to remove CMakeCache.txt.")
 endif()
 
 project(libyang C)
 
 # include custom Modules
-set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/CMakeModules/")
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules/")
 
 include(GNUInstallDirs)
 include(CheckSymbolExists)