error I\'m receiving is this
directory not found for option \'-F/Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/De
After much digging, I found this is actually related to my test target of my app.
The Fix
If you select your project, and look under ‘Targets’, you should see two targets. One is your app and the other one is your test. Under ‘Search Paths’ (in my test target), I found it was including two items under ‘Framework Search Paths’:
$(SDKROOT)/Developer/Library/Frameworks $(inherited)
Deleting those entries in my older project then removed the warning. I did not have to make any changes to the other target.