/in/foo.cc: In function 'bool COWtest()':
/in/foo.cc:91:30: warning: array subscript has type 'char' [-Wchar-subscripts]
  for(int i=0;i<len;i++)L[x[i]]++;
                              ^
/in/foo.cc:92:30: warning: array subscript has type 'char' [-Wchar-subscripts]
  for(int i=0;i<47;i++)M[bl[i]]++;
                              ^