bug#4616: 23.1.50; empty script files

One more thing about unread_char in lread.c.  That variable should
start with value -1 rather than value 0.  The current initial value 0
means that the character 0 is added in front of loadup.el when
building emacs.  Now since loadup.el isn't empty, this doesn't cause
a read error, the additional character will be just skipped and the
value of unread_char is set to -1 after loading loadup.el.

So one doesn't notice the wrong initial value.  But maybe one changes
that for clarity.


*** lread.c	06 Oct 2009 14:22:15 +0200	1.414
--- lread.c	06 Oct 2009 17:01:06 +0200	
***************
*** 270,276 ****
     Qlambda, or a cons, we use this to keep an unread character because
     a file stream can't handle multibyte-char unreading.  The value -1
     means that there's no unread character. */
! static int unread_char;
  
  static int
  readchar (readcharfun, multibyte)
--- 270,276 ----
     Qlambda, or a cons, we use this to keep an unread character because
     a file stream can't handle multibyte-char unreading.  The value -1
     means that there's no unread character. */
! static int unread_char = -1;
  
  static int
  readchar (readcharfun, multibyte)