Disable library correctly if dependency was not found

source/RobotAPI/libraries/DSControllers/CMakeLists.txt

@@ -5,10 +5,11 @@ armarx_set_target("Library: ${LIB_NAME}")
 
 find_package(Eigen3 QUIET)
 find_package(Simox ${ArmarX_Simox_VERSION} QUIET)
-
 find_package(MATHLIB QUIET)
+
 armarx_build_if(Eigen3_FOUND "Eigen3 not available")
 armarx_build_if(Simox_FOUND "Simox-VirtualRobot not available")
+armarx_build_if(MATHLIB_FOUND "MATHLIB not available")
 
 if (Eigen3_FOUND AND Simox_FOUND)
     include_directories(${Simox_INCLUDE_DIRS})