Warnings about Universal Type Identifier which can't be defined when using plugin

[Richard B.]

          As the warnings are still present, I dig to determine where they are coming from:

https://developer.apple.com/documentation/security/app_sandbox/discovering_and_diagnosing_app_sandbox_violations

To get the detail error:

swiftgen: warning: Unable to determine the Universal Type Identifier for file /Users/kenji/.....path-to-Regular.ttf : Error Domain=NSCocoaErrorDomain Code=256 "The file “Regular.ttf” couldn’t be opened." UserInfo={NSURL=file:///Users/kenji/.....path-to-Regular.ttf, NSFilePath=/Users/kenji/.....path-to-Regular.ttf, NSUnderlyingError=0x12d631cd0 {Error Domain=NSOSStatusErrorDomain Code=-10813 "kLSDataUnavailableErr: E.g. no kind string"}}

using /usr/bin/sandbox-exec with all the options, only replacing plugin command to: /Users/kenji/github/SwiftGen/.build/debug/swiftgen

and after patching (and swift build):

Originally posted by @kenji21 in #952 (comment)