add new build error and solution to Mac build

docs/build/build-errors.md

@@ -166,6 +166,29 @@ For example, if you see "Invalid active developer path (/Library/Developer/Comma
 
 ## Specific Error Messages
 
+### Unable to read included file `LoopConfigOverride.xcconfig`
+
+**Error Message:**  
+This error occurs inside *Xcode* with the build halting at the line that reads the `LoopConfigOverride.xcconfig` file.
+
+![xcode does not have permission to read downloads folder](img/xcode-permission-error.jpg){width="650"}
+{align="center"}
+
+**Solution:**
+
+Modify the permissions for *Xcode* in your macOS.
+
+The graphic below has steps labeled 1 through 4 to guide you to the setting that must be enabled for you to build the app with *Xcode*.
+
+1. Open the macOS settings (*Apple* icon) and navigate to Privacy & Security
+1. Select Files and Folders
+1. Select *Xcode*
+1. Ensure that Downloads Folder is enabled
+
+![check privacy settings for xcode access to downloads folder](img/set-xcode-file-permissions.png){width="750"}
+{align="center"}
+
+
 ### No devices from which to generate a provisioning profile
 
 **Error Message:**  

docs/build/xcode-settings.md

@@ -18,6 +18,15 @@ Open Xcode from your Applications folder. If it offers to start a new project wi
 
 Click on the Xcode->About Xcode menu item. The version number is displayed.
 
+## Privacy Settings
+
+This is not typical, but it does happen.
+
+Some people have their macOS privacy settings configured so that *Xcode* does not have permission to access their `~/Downloads` folder. This will cause a lot of grief when trying to use the Build Select Script to build an app with *Xcode*. This will be mentioned on the build errors page, but this is a good time to check. The graphic below has steps labeled 1 through 4 to guide you to the setting that must be enabled for you to build the app with *Xcode*.
+
+![check privacy settings for xcode access to downloads folder](img/set-xcode-file-permissions.png){width="750"}
+{align="center"}
+
 ## watchOS Simulators
 
 Yes, watchOS simulators are required to build Loop. If Xcode asks if you want to download them - say yes. It's slow but you cannot build Loop without the simulator.