Fix issue when using file(GLOB_RECURSE... in top level directory

CMakeLists.txt

@@ -10,8 +10,12 @@ add_compile_definitions(LOG4TANGO_HAVE_INT64_T)
 add_compile_definitions(GPIB_DEVICE_OUTSIDE)
 add_compile_definitions(USE_HELPERS_DIR)
 
-file(GLOB_RECURSE sources
-    ${CMAKE_SOURCE_DIR}/*.cpp
+set(sources
+    ClassFactory.cpp
+    Keithley428Class.cpp       
+    Keithley428.cpp
+    Keithley428StateMachine.cpp
+    main.cpp
 )
 
 set(includedirs