module Rake::TraceOutput

def trace_on(out, *strings)

producing output.
chance that the trace output is interrupted by other tasks also
The write is done as a single IO call (to print) to lessen the

Write trace output to output stream +out+. 
def trace_on(out, *strings)
  sep = $\ || "\n"
  if strings.empty?
    output = sep
  else
    output = strings.map { |s|
      next if s.nil?
      s.end_with?(sep) ? s : s + sep
    }.join
  end
  out.print(output)
end