[partition] Handle missing requirements by disabling the module

src/modules/partition/CMakeLists.txt

@@ -5,14 +5,19 @@ include(GenerateExportHeader)
 find_package( Qt5 REQUIRED DBus )
 find_package( KF5 REQUIRED Config CoreAddons I18n WidgetsAddons )
 
-find_package( KPMcore 3.3 REQUIRED )
+find_package( KPMcore 3.3 )
+set_package_properties(
+    KPMcore PROPERTIES
+    PURPOSE "For partitioning module"
+)
 
-include_directories( ${KPMCORE_INCLUDE_DIR} )
-include_directories( ${PROJECT_BINARY_DIR}/src/libcalamaresui )
+if ( KPMcore_FOUND )
+    include_directories( ${KPMCORE_INCLUDE_DIR} )
+    include_directories( ${PROJECT_BINARY_DIR}/src/libcalamaresui )
 
-add_subdirectory( tests )
+    add_subdirectory( tests )
 
-calamares_add_plugin( partition
+    calamares_add_plugin( partition
         TYPE viewmodule
         EXPORT_MACRO PLUGINDLLEXPORT_PRO
         SOURCES
@@ -65,4 +70,7 @@ calamares_add_plugin( partition
             calamaresui
             KF5::CoreAddons
         SHARED_LIB
-)
+    )
+else()
+    calamares_skip_module( "partition (missing suitable KPMcore)" )
+endif()