diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,6 +12,14 @@
 find_package (ECM 5.14.0 REQUIRED NO_MODULE)
 set(CMAKE_MODULE_PATH ${KDevelop_SOURCE_DIR}/cmake/modules ${ECM_MODULE_PATH})
 
+if(NOT CMAKE_VERSION VERSION_LESS "3.10.0")
+  # CMake 3.9+ warns about automoc on files without Q_OBJECT, and doesn't know about other macros.
+  # 3.10+ lets us provide more macro names that require automoc.
+  # Remove this when depending on a Frameworks or ECM version that solves this upstream.
+  list(APPEND CMAKE_AUTOMOC_MACRO_NAMES
+       "K_PLUGIN_FACTORY_WITH_JSON" "K_EXPORT_PLASMA_DATAENGINE_WITH_JSON" "K_EXPORT_PLASMA_RUNNER")
+endif()
+
 include(KDECompilerSettings NO_POLICY_SCOPE) # needs to be first, as set policies influence following macros
 include(ECMOptionalAddSubdirectory)
 include(ECMInstallIcons)