This patch fixes a bug in XVs gif-reading code.  The bug could conceivably
hit when viewing a number of interlaced GIFs.  Thanks to Mark Hanson 
<mbh@netcom.com> for spotting this one.  

--jhb, 10/29/98


*** xvgif.c.old	Tue Jan 10 14:54:41 1995
--- xvgif.c	Thu Oct 29 17:43:30 1998
***************
*** 113,119 ****
    int            aspect, gotimage;
  
    /* initialize variables */
!   BitOffset = XC = YC = Pass = OutCount = gotimage = 0;
    RawGIF = Raster = pic8 = NULL;
    gif89 = 0;
  
--- 113,120 ----
    int            aspect, gotimage;
  
    /* initialize variables */
!   BitOffset = XC = YC = OutCount = gotimage = 0;
!   Pass = -1;
    RawGIF = Raster = pic8 = NULL;
    gif89 = 0;
  
***************
*** 692,698 ****
  {
    static byte *ptr = NULL;
    static int   oldYC = -1;
!   
    if (oldYC != YC) {  ptr = pic8 + YC * Width;  oldYC = YC; }
    
    if (YC<Height)
--- 693,704 ----
  {
    static byte *ptr = NULL;
    static int   oldYC = -1;
! 
!   if (Pass == -1) {  /* first time through - init stuff */
!     oldYC = -1;
!     Pass = 0;
!   }
! 
    if (oldYC != YC) {  ptr = pic8 + YC * Width;  oldYC = YC; }
    
    if (YC<Height)