Xcode integration broken

[sergiocampama]

This might be more about Xcode's plugin support for generated files, but when building with Xcode I'm getting this error:

error: Build input file cannot be found: '~/Library/Developer/Xcode/DerivedData/xls-awobgocixipoyadtahkpiowejftk/Build/Products/Debug/SwiftJavaTool'. Did you forget to declare this file as an output of a script phase or custom build rule which produces it? (in target 'xls_xls' from project 'xls')

Building on the command line works as expected, but I'd like to get autocompletion on a more comfortable IDE like Xcode.