canon: fix [-Wunused-but-set-variable] compiler warnings

backend/canon-sane.c

@@ -1104,7 +1104,6 @@ sane_get_parameters (SANE_Handle handle, SANE_Parameters *params)
 SANE_Status
 sane_start (SANE_Handle handle)
 {
-  int mode;
   char *mode_str;
   CANON_Scanner *s = handle;
   SANE_Status status;
@@ -1301,33 +1300,27 @@ sane_start (SANE_Handle handle)
 
   if (!strcmp (mode_str, SANE_VALUE_SCAN_MODE_LINEART))
     {
-      mode = 4;
       s->image_composition = 0;
     }
   else if (!strcmp (mode_str, SANE_VALUE_SCAN_MODE_HALFTONE))
     {
-      mode = 4;
       s->image_composition = 1;
     }
   else if (!strcmp (mode_str, SANE_VALUE_SCAN_MODE_GRAY))
     {
-      mode = 5;
       s->image_composition = 2;
     }
   else if (!strcmp (mode_str, SANE_VALUE_SCAN_MODE_COLOR)
   || !strcmp (mode_str, SANE_I18N("Fine color")))
     {
-      mode = 6;
       s->image_composition = 5;
     }
   else if (!strcmp (mode_str, SANE_I18N("Raw")))
     {
-      mode = 6;
       s->image_composition = 5;
     }
   else
     {
-      mode = 6;
       s->image_composition = 5;
     }
 

backend/canon-scsi.c

@@ -688,7 +688,7 @@ static SANE_Status
 set_parameters_fs2710 (SANE_Handle handle)
 {
   CANON_Scanner *s = handle;
-  int i, j, invert, shadow[4], hilite[4];
+  int i, j, shadow[4], hilite[4];
   double x, b, c;
 
   shadow[1] = s->ShadowR << 4;
@@ -700,8 +700,6 @@ set_parameters_fs2710 (SANE_Handle handle)
   c = ((double) s->contrast) / 128.0;
   b = ((double) (s->brightness - 128)) / 128.0;
 
-  invert = strcmp (filmtype_list[1], s->val[OPT_NEGATIVE].s);
-
   for (i = 1; i < 4; i++)
     {
       for (j = 0; j < 4096; j++)