cmake: only disable libpng-apng in intel mac CI, not for self builds.

A test locally worked just fine on my end... (2018 MBP)

Author: adriweb

gui/qt/CMakeLists.txt

@@ -284,16 +284,16 @@ if(PkgConfig_FOUND)
     endif()
 endif()
 
-if(APPLE AND NOT (CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "arm64"))
-    message("For now, libpng-apng is disabled on intel macs... see issue #528. APNG capture will not be available")
+if((DEFINED ENV{GITHUB_ACTION}) AND APPLE AND NOT (CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL "arm64"))
+    message("For now, libpng-apng is disabled on intel macs on CI... see issue #528. APNG capture will not be available")
 else()
     find_package(PNG QUIET)
     if(PNG_FOUND)
         include(CheckSymbolExists)
         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")
+            list(APPEND CMAKE_AUTOMOC_MOC_OPTIONS "-DPNG_SUPPORT" "-DPNG_WRITE_APNG_SUPPORTED")
             target_compile_definitions(CEmu PRIVATE "PNG_SUPPORT")
             target_link_libraries(CEmu PRIVATE PNG::PNG)
         else()