cmake: Fix Xcode version error message

cmake/macos/compilerconfig.cmake

@@ -28,11 +28,11 @@ set(_obs_macos_minimum_xcode 15.1) # Keep in sync with SDK
 message(DEBUG "macOS SDK Path: ${CMAKE_OSX_SYSROOT}")
 string(REGEX MATCH ".+/MacOSX.platform/Developer/SDKs/MacOSX([0-9]+\\.[0-9])+\\.sdk$" _ ${CMAKE_OSX_SYSROOT})
 set(_obs_macos_current_sdk ${CMAKE_MATCH_1})
-message(DEBUG "macOS SDK version: ${OBS_MACOS_CURRENT_SDK}")
+message(DEBUG "macOS SDK version: ${_obs_macos_current_sdk}")
 if(_obs_macos_current_sdk VERSION_LESS _obs_macos_minimum_sdk)
   message(
-    FATAL_ERROR "Your macOS SDK version (${OBS_MACOS_CURRENT_SDK}) is too low. "
-                "The macOS ${OBS_MACOS_MINIMUM_SDK} SDK (Xcode ${OBS_MACOS_MINIMUM_XCODE}) is required to build OBS.")
+    FATAL_ERROR "Your macOS SDK version (${_obs_macos_current_sdk}) is too low. "
+                "The macOS ${_obs_macos_minimum_sdk} SDK (Xcode ${_obs_macos_minimum_xcode}) is required to build OBS.")
 endif()
 unset(_obs_macos_current_sdk)
 unset(_obs_macos_minimum_sdk)