cmake: libpng-apng: adjust AUTOMOC_MOC_OPTIONS even more

Author: adriweb

gui/qt/CMakeLists.txt

@@ -293,7 +293,7 @@ else()
         set(CMAKE_REQUIRED_INCLUDES ${PNG_INCLUDE_DIRS})
         check_symbol_exists(PNG_WRITE_APNG_SUPPORTED "png.h" HAVE_PROPER_APNG_LIB)
         if(HAVE_PROPER_APNG_LIB)
-            set_property(TARGET CEmu PROPERTY AUTOMOC_MOC_OPTIONS "-DPNG_WRITE_APNG_SUPPORTED")
+            set_property(TARGET CEmu APPEND PROPERTY AUTOMOC_MOC_OPTIONS "-DPNG_SUPPORT" "-DPNG_WRITE_APNG_SUPPORTED")
             target_compile_definitions(CEmu PRIVATE "PNG_SUPPORT")
             target_link_libraries(CEmu PRIVATE PNG::PNG)
         else()