Fix paths in CMake (libSGM)

lib/libsgm/src/CMakeLists.txt

@@ -31,12 +31,12 @@ install(
 )
 
 install(
-	DIRECTORY ${CMAKE_SOURCE_DIR}/include
+	DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/../include
 	DESTINATION ${CMAKE_INSTALL_PREFIX}
 	FILES_MATCHING PATTERN "*.h" PATTERN "*.hpp"
 )
 
 install(
-	FILES ${CMAKE_SOURCE_DIR}/FindLibSGM.cmake
+	FILES ${CMAKE_CURRENT_SOURCE_DIR}/../FindLibSGM.cmake
 	DESTINATION ${CMAKE_INSTALL_PREFIX}
 )