cmake: Check if Sparkle options are non-empty

UI/CMakeLists.txt

@@ -446,7 +446,7 @@ elseif(OS_MACOS)
               update/shared-update.cpp update/shared-update.hpp
               update/update-helpers.cpp update/update-helpers.hpp)
 
-    if(DEFINED SPARKLE_APPCAST_URL AND DEFINED SPARKLE_PUBLIC_KEY)
+    if(SPARKLE_APPCAST_URL AND SPARKLE_PUBLIC_KEY)
       find_library(SPARKLE Sparkle)
       mark_as_advanced(SPARKLE)
 

cmake/Modules/ObsHelpers_macOS.cmake

@@ -354,7 +354,7 @@ function(setup_obs_bundle target)
     set(_CODESIGN_ENTITLEMENTS \"${CMAKE_SOURCE_DIR}/cmake/bundle/macOS\")"
     COMPONENT obs_resources)
 
-  if(DEFINED SPARKLE_APPCAST_URL AND DEFINED SPARKLE_PUBLIC_KEY)
+  if(SPARKLE_APPCAST_URL AND SPARKLE_PUBLIC_KEY)
     add_custom_command(
       TARGET ${target}
       POST_BUILD