You'll need to apply the following (trivial) patch to get XV 3.10a to compile
with version 6 of the Independent JPEG Group's JPEG library, which
supports progressive JPEG and such.  

Note that XV 3.10a is still shipped with version 5a of said library.  If 
you'd like the newer library, it is available for anonymous ftp at this
location:  ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz

John Bradley
-----------------------------------------------------------------------------


*** xvjpeg.c.old	Thu Jan  5 03:17:13 1995
--- xvjpeg.c	Tue Jul 23 16:37:01 1996
***************
*** 51,61 ****
  static    void         clickJD            PARM((int, int));
  static    void         doCmd              PARM((int));
  static    void         writeJPEG          PARM((void));
! METHODDEF void         xv_error_exit      PARM((j_common_ptr));
! METHODDEF void         xv_error_output    PARM((j_common_ptr));
! METHODDEF void         xv_prog_meter      PARM((j_common_ptr));
  static    unsigned int j_getc             PARM((j_decompress_ptr));
! METHODDEF boolean      xv_process_comment PARM((j_decompress_ptr));
  static    int          writeJFIF          PARM((FILE *, byte *, int,int,int));
  
  
--- 51,61 ----
  static    void         clickJD            PARM((int, int));
  static    void         doCmd              PARM((int));
  static    void         writeJPEG          PARM((void));
! METHODDEF(void)        xv_error_exit      PARM((j_common_ptr));
! METHODDEF(void)        xv_error_output    PARM((j_common_ptr));
! METHODDEF(void)        xv_prog_meter      PARM((j_common_ptr));
  static    unsigned int j_getc             PARM((j_decompress_ptr));
! METHODDEF(boolean)     xv_process_comment PARM((j_decompress_ptr));
  static    int          writeJFIF          PARM((FILE *, byte *, int,int,int));
  
  
***************
*** 400,406 ****
  
  
  /**************************************************/
! METHODDEF void xv_error_exit(cinfo) 
       j_common_ptr cinfo;
  {
    my_error_ptr myerr;
--- 400,406 ----
  
  
  /**************************************************/
! METHODDEF(void) xv_error_exit(cinfo) 
       j_common_ptr cinfo;
  {
    my_error_ptr myerr;
***************
*** 412,418 ****
  
  
  /**************************************************/
! METHODDEF void xv_error_output(cinfo) 
       j_common_ptr cinfo;
  {
    my_error_ptr myerr;
--- 412,418 ----
  
  
  /**************************************************/
! METHODDEF(void) xv_error_output(cinfo) 
       j_common_ptr cinfo;
  {
    my_error_ptr myerr;
***************
*** 426,432 ****
  
  
  /**************************************************/
! METHODDEF void xv_prog_meter(cinfo)
       j_common_ptr cinfo;
  {
    struct jpeg_progress_mgr *prog;
--- 426,432 ----
  
  
  /**************************************************/
! METHODDEF(void) xv_prog_meter(cinfo)
       j_common_ptr cinfo;
  {
    struct jpeg_progress_mgr *prog;
***************
*** 671,677 ****
  
  
  /**************************************************/
! METHODDEF boolean xv_process_comment(cinfo)
       j_decompress_ptr cinfo;
  {
    int          length, hasnull;
--- 671,677 ----
  
  
  /**************************************************/
! METHODDEF(boolean) xv_process_comment(cinfo)
       j_decompress_ptr cinfo;
  {
    int          length, hasnull;