include "this file does not exist"

# (include (@ 1 0-7) ‘this file does not exist’
#   (.inner nil)
# )
# this file does not exist: error: no such file or directory in ‘.../test-files/mds-kbdc/process-includes/invalid’
# 
# .../test-files/mds-kbdc/process-includes/invalid/include_nonexisting:1:0–7: note: included from here
#  include "this file does not exist"
#  ^^^^^^^