citra-qt: Add icon to Mac app

Previously the Mac app didn't have any icon.

src/citra_qt/CMakeLists.txt

@@ -72,7 +72,9 @@ else()
 endif()
 
 if (APPLE)
-    add_executable(citra-qt MACOSX_BUNDLE ${SRCS} ${HEADERS} ${UI_HDRS})
+    set(MACOSX_ICON "../../dist/citra.icns")
+    set_source_files_properties(${MACOSX_ICON} PROPERTIES MACOSX_PACKAGE_LOCATION Resources)
+    add_executable(citra-qt MACOSX_BUNDLE ${SRCS} ${HEADERS} ${UI_HDRS} ${MACOSX_ICON})
     set_target_properties(citra-qt PROPERTIES MACOSX_BUNDLE_INFO_PLIST ${CMAKE_CURRENT_SOURCE_DIR}/Info.plist)
 else()
     add_executable(citra-qt ${SRCS} ${HEADERS} ${UI_HDRS})