To build with partitionmanager: cmake -DWITH_PARTITIONMANAGER=1

src/libcalamares/CMakeLists.txt

 project( calamareslib )
 
+if( WITH_PARTITIONMANAGER )
 add_subdirectory( partitionmanager/calamares )
+endif()
 
 add_definitions( ${QT_DEFINITIONS} )
 add_definitions( -DQT_SHARED )

tests/CMakeLists.txt

+if( WITH_PARTITIONMANAGER )
 add_executable(calapmtest calapmtest.cpp)
 add_definitions(-DCALAMARES)
 target_link_libraries(calapmtest calapm Qt5::Core)
+endif()