Make doctools optional

CMakeLists.txt

@@ -87,7 +87,6 @@ find_package(KF5ConfigWidgets ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5CoreAddons ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5Crash ${KF5_MIN_VERSION} REQUIRED)
 find_package(KF5DBusAddons ${KF5_MIN_VERSION} CONFIG REQUIRED)
-find_package(KF5DocTools ${KF5_MIN_VERSION} REQUIRED)
 find_package(KF5IconThemes ${KF5_MIN_VERSION} REQUIRED)
 find_package(KF5ItemViews ${KF5_MIN_VERSION} REQUIRED)
 find_package(KF5JobWidgets ${KF5_MIN_VERSION} REQUIRED)
@@ -101,6 +100,13 @@ find_package(KF5XmlGui ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5Notifications ${KF5_MIN_VERSION} CONFIG REQUIRED)
 find_package(KF5Holidays ${KF5_MIN_VERSION} CONFIG REQUIRED)
 
+find_package(KF5DocTools ${KF5_MIN_VERSION})
+set_package_properties(KF5DocTools PROPERTIES DESCRIPTION
+    "Tools to generate documentation"
+    TYPE OPTIONAL
+)
+
+
 # Find KdepimLibs Package
 find_package(KF5PimTextEdit ${KPIMTEXTEDIT_LIB_VERSION} CONFIG REQUIRED)
 find_package(KF5Akonadi ${AKONADI_VERSION} CONFIG REQUIRED)
@@ -161,8 +167,12 @@ ecm_qt_install_logging_categories(
         DESTINATION ${KDE_INSTALL_LOGGINGCATEGORIESDIR}
         )
 
-add_subdirectory(doc)
 kde_configure_git_pre_commit_hook(CHECKS CLANG_FORMAT)
 ki18n_install(po)
-kdoctools_install(po)
+
+if(KF5DocTools_FOUND)
+    kdoctools_install(po)
+    add_subdirectory(doc)
+endif()
+
 feature_summary(WHAT ALL FATAL_ON_MISSING_REQUIRED_PACKAGES)