Fix annoying warning

Summary:
Warning for every plugin was:
The file includes the moc file "generator_tiff.moc", but does not contain a Q_OBJECT, Q_GADGET, Q_NAMESPACE, K_PLUGIN_FACTORY_WITH_JSON, K_PLUGIN_FACTORY, K_PLUGIN_FACTORY_WITH_JSON or K_PLUGIN_FACTORY macro.

Test Plan: Built

Reviewers: aacid

Reviewed By: aacid

Subscribers: #okular

Tags: #okular

Differential Revision: https://phabricator.kde.org/D10022

CMakeLists.txt

@@ -40,6 +40,12 @@ else()
     add_definitions(-DHAVE_SPEECH)
 endif()
 
+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.
+  list(APPEND CMAKE_AUTOMOC_MACRO_NAMES "OKULAR_EXPORT_PLUGIN")
+endif()
+
 find_package(KF5 ${KF5_REQUIRED_VERSION} REQUIRED COMPONENTS
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