A note WRT c2str.pl

[Leopold Toetsch]

I've now changed interpreter.c to use CONST_STRING() too. It's basically 
working but there is a problem:
The macros use the current line number for identifying a string. When 
the line is:

  f (some,
  CONST_STRING("foo"),
  some_more);
then c2str.pl and the C compiler have different line numbers.
So CONST_STRING() has to be on the last line of one statement.
leo