[commited] Allow a line number of zero in .appline

[Nick Clifton <nickc at redhat dot com>]

Hi Guys,

  I am applying the patch below to allow line numbers of zero when
  processing the .appline directive.  This is because GCC will
  generate such line numbers when it pre-processes an assembler file.
  eg:

    $ cat foo.S
    nop
    $ gcc -c foo.S --save-temps
    foo.S:1: Warning: line numbers must be positive; line number 0 rejected

    $ cat foo.s
    # 1 "foo.S"
    # 0 "<built-in>"
    # 1 "<command line>"
    # 1 "foo.S"
    nop

  I am not sure whether technically the number zero counts as a
  positive number, but I do feel that we should accept it.

Cheers
  Nick

gas/ChangeLog
2005-08-07  Nick Clifton  <nickc@redhat.com>

	* read.c (s_app_line): Accept a line number of 0 for compatibility
	with gcc's output for assembler-with-cpp files.

Index: gas/read.c
===================================================================
RCS file: /cvs/src/src/gas/read.c,v
retrieving revision 1.104
diff -c -3 -p -r1.104 read.c
*** gas/read.c	17 May 2005 14:02:27 -0000	1.104
--- gas/read.c	7 Aug 2005 10:26:41 -0000
*************** s_app_line (int ignore ATTRIBUTE_UNUSED)
*** 1698,1706 ****
  
    /* The given number is that of the next line.  */
    l = get_absolute_expression () - 1;
!   if (l < 0)
      /* Some of the back ends can't deal with non-positive line numbers.
!        Besides, it's silly.  */
      as_warn (_("line numbers must be positive; line number %d rejected"),
  	     l + 1);
    else
--- 1698,1714 ----
  
    /* The given number is that of the next line.  */
    l = get_absolute_expression () - 1;
! 
!   if (l < -1)
      /* Some of the back ends can't deal with non-positive line numbers.
!        Besides, it's silly.  GCC however will generate a line number of
!        zero when it is preprocessing builtins for assembler-with-cpp files:
! 
!           # 0 "<built-in>"
! 
!        We do not want to barf on this, especially since such files are used
!        in the GCC and GDB testsuites.  So we check for negative line numbers
!        rather than non-positive line numbers.  */
      as_warn (_("line numbers must be positive; line number %d rejected"),
  	     l + 1);
    else