Added header guards for CMake add_subdirectory

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.03)
 
 project(midas_lan_gpib VERSION 0.1)
 
-# If the target already exists in a project (e.g. if midas_lan_gpib is included multiple time as a submodule of submodules),
+# If the target already exists in a project (e.g. if lan_gpib_vxi11_linux_64bit is included multiple time as a submodule of submodules),
 # this "header guard"-style check prevents defining the same target multiple times (which will lead to CMake errors).
 if(TARGET midas_lan_gpib)
   return()
@@ -25,11 +25,6 @@ set(
   $ENV{MIDASSYS}/drivers/class/generic.cxx
 )
 
-# guard against multiple include
-if(NOT TARGET lan_gpib_vxi11_linux_64bit) 
-  add_subdirectory(lan_gpib_vxi11)
-endif()
-
 set(SYS_LIBS
     pthread
     util
@@ -45,6 +40,10 @@ set(MIDAS_LIBS
 
 set(LIBS ${SYS_LIBS} ${MIDAS_LIBS})
 
+if(NOT TARGET lan_gpib_vxi11_linux_64bit)
+  add_subdirectory(lan_gpib_vxi11)
+endif()
+
 ################################################################################
 ## Bus library
 ################################################################################