Make it possible to incrementally supply OSC_NOTARIZATION/OSC_CODESIGN variables without over-caching

Author: adamkewley

packaging/MacOS/Packaging.cmake

@@ -64,6 +64,7 @@ endif()
 if(OSC_CODESIGN_ENABLED)
     set(OSC_CODESIGN_DEVELOPER_ID "$ENV{OSC_CODESIGN_DEVELOPER_ID}" CACHE STRING "The developer ID string for the codesigning key (e.g. 'Developer ID Application: Some Developer (XYA12398BF)'). Get it with `security find-identity -p codesigning -v`")
     if(NOT OSC_CODESIGN_DEVELOPER_ID)
+        unset(OSC_CODESIGN_DEVELOPER_ID UNSET)
         message(FATAL_ERROR "OSC_CODESIGN_DEVELOPER_ID must be set if OSC_CODESIGN_ENABLED is on")
     endif()
 
@@ -95,12 +96,15 @@ if(OSC_NOTARIZATION_ENABLED)
     set(OSC_NOTARIZATION_PASSWORD "$ENV{OSC_NOTARIZATION_PASSWORD}" CACHE STRING "App-specific password of the signer (you can create this from your apple ID account)")
 
     if(NOT OSC_NOTARIZATION_APPLE_ID)
+        unset(OSC_NOTARIZATION_APPLE_ID CACHE)
         message(FATAL_ERROR "OSC_NOTARIZATION_APPLE_ID must be set if OSC_NOTARIZATION_ENABLED is on")
     endif()
     if(NOT OSC_NOTARIZATION_TEAM_ID)
+        unset(OSC_NOTARIZATION_TEAM_ID CACHE)
         message(FATAL_ERROR "OSC_NOTARIZATION_TEAM_ID must be set if OSC_NOTARIZATION_ENABLED is on")
     endif()
     if(NOT OSC_NOTARIZATION_PASSWORD)
+        unset(OSC_NOTARIZATION_PASSWORD CACHE)
         message(FATAL_ERROR "OSC_NOTARIZATION_PASSWORD must be set if OSC_NOTARIZATION_ENABLE is on")
     endif()