anchor.diff:  LANGUAGE=de R
   require(data.table)
   test.data.table()
  +q("no")
   
   R
   remove.packages("xml2")    # we checked the URLs; don't need to do it again (many minutes)
   require(data.table)
   test.data.table()
  -test.data.table(with.other.packages=TRUE)
  +test.data.table(script="other.Rraw")
   test.data.table(verbose=TRUE)   # since main.R no longer tests verbose mode
   gctorture2(step=50)
   system.time(test.data.table())  # apx 4hrs
  
positive.code: 
  cd ..
  R
  cc(clean=TRUE)  # to compile with -pedandic. Also use very latest gcc (currently gcc-7) as CRAN does
  saf = options()$stringsAsFactors
  options(stringsAsFactors=!saf)    # check tests (that might be run by user) are insensitive to option, #2718
  test.data.table()
  
negative.code: grep --exclude="./src/openmp-utils.c" omp_get_max_threads ./src/*
  
  # Ensure all #pragama omp parallel directives include a num_threads() clause
  grep "pragma omp parallel" ./src/*.c | grep -v getDTthreads
  
  # Ensure all .Call's first argument are unquoted.
  grep "[.]Call(\"" ./R/*.R
  
  # Ensure no Rprintf in init.c
  