Prepare to disable MbsApi

An option BUILD_MBS is already available.
Setting it to OFF breaks the build currently.
So let's fix all those things.

But still keep the default at ON to make sure, that
compiling with BUILD_MBS=ON works now, at least.

Author: ChristianTackeGSI

CMakeLists.txt

@@ -291,7 +291,9 @@ else()
   Set(ROOT_HAS_OPENGL FALSE)
 endif()
 
-add_subdirectory(MbsAPI)
+if(BUILD_MBS)
+  add_subdirectory(MbsAPI)
+endif()
 add_subdirectory(datamatch)
 
 add_subdirectory(templates)

base/MQ/CMakeLists.txt

@@ -67,7 +67,6 @@ target_include_directories(${target} PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/policies/Sampler>
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/policies/Serialization>
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/policies/Storage>
-  $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/MbsAPI>
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
 
   # TODO: DELETE ME ONCE USING root targets

examples/CMakeLists.txt

@@ -33,9 +33,13 @@ if(Geant3_FOUND)
   add_subdirectory(simulation/rutherford)
 endif()
 
+if(BUILD_MBS)
+  add_subdirectory(advanced/MbsTutorial)
+endif()
+
 if(FairMQ_FOUND AND Boost_FOUND)
-  add_subdirectory(MQ/Lmd)
+  if(BUILD_MBS)
+    add_subdirectory(MQ/Lmd)
+  endif()
   add_subdirectory(MQ/histogramServer)
 endif()
-
-add_subdirectory(advanced/MbsTutorial)