Fix -Wimplicit-fallthrough warnings by adding standard annotations

backend/agfafocus.c

@@ -1485,6 +1485,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	case OPT_BR_Y:
 	  if (info)
 	    *info |= SANE_INFO_RELOAD_PARAMS;
+          // fall through
 	case OPT_SHARPEN:
 	case OPT_EXPOSURE:
 	case OPT_ATTENUATION_RED:

backend/apple.c

@@ -2065,6 +2065,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	DBG (FLOW_CONTROL, "Value %g (Fixed)\n",
 	     (action == SANE_ACTION_GET_VALUE) ? v1 : v2);
         }
+        // fall through
       default:
 	DBG (FLOW_CONTROL, "Value %u (Int).\n",
 		(action == SANE_ACTION_GET_VALUE)

backend/epson2.c

@@ -1894,7 +1894,7 @@ setvalue(SANE_Handle handle, SANE_Int option, void *value, SANE_Int *info)
 			DBG(17, "invalid br-x or br-y\n");
 			return SANE_STATUS_INVAL;
 		}
-		/* passthru */
+		// fall through
 	case OPT_TL_X:
 	case OPT_TL_Y:
 		sval->w = *((SANE_Word *) value);

backend/epsonds.c

@@ -1055,7 +1055,7 @@ setvalue(SANE_Handle handle, SANE_Int option, void *value, SANE_Int *info)
 			DBG(17, " invalid br-x or br-y\n");
 			return SANE_STATUS_INVAL;
 		}
-		/* passthru */
+		// fall through
 	case OPT_TL_X:
 	case OPT_TL_Y:
 		sval->w = *((SANE_Word *) value);

backend/hp3900_sane.c

@@ -1991,6 +1991,7 @@ option_get (TScanner * scanner, SANE_Int optid, void *result)
 	  /* scanner buttons */
 	case opt_button_0:
 	  get_button_status (scanner);
+          // fall through
 	case opt_button_1:
 	case opt_button_2:
 	case opt_button_3:

backend/kodakaio.c

@@ -3281,7 +3281,7 @@ setvalue(SANE_Handle handle, SANE_Int option, void *value, SANE_Int *info)
 			DBG(17, "invalid br-x or br-y\n");
 			return SANE_STATUS_INVAL;
 		}
-		/* passthru */
+                // fall through
 	case OPT_TL_X:
 	case OPT_TL_Y:
 		sval->w = *((SANE_Word *) value);

backend/magicolor.c

@@ -2794,7 +2794,7 @@ setvalue(SANE_Handle handle, SANE_Int option, void *value, SANE_Int *info)
 			DBG(17, "invalid br-x or br-y\n");
 			return SANE_STATUS_INVAL;
 		}
-		/* passthru */
+		// fall through
 	case OPT_TL_X:
 	case OPT_TL_Y:
 		sval->w = *((SANE_Word *) value);

backend/microtek.c

@@ -3444,6 +3444,7 @@ sane_control_option (SANE_Handle handle,
     case OPT_RESOLUTION:
       if (info)
 	*info |= SANE_INFO_RELOAD_PARAMS;
+      // fall through
     case OPT_SPEED:
     case OPT_PREVIEW:
     case OPT_BACKTRACK:

backend/nec.c

@@ -2306,6 +2306,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	case OPT_BR_Y:
 	  if (info && s->val[option].w != *(SANE_Word *) val)
 	    *info |= SANE_INFO_RELOAD_PARAMS;
+          // fall through
 	case OPT_NUM_OPTS:
 	case OPT_THRESHOLD:
 	  /* xxx theoretically, we could use OPT_THRESHOLD in

backend/pixma_bjnp.c

@@ -2518,8 +2518,7 @@ sanei_bjnp_read_int (SANE_Int dn, SANE_Byte * buffer, size_t * size)
         }
       device[dn].polling_status = BJNP_POLL_STARTED;
 
-      /* fall through to BJNP_POLL_STARTED */
-
+      // fall through
     case BJNP_POLL_STARTED:
       /* we use only seonds accuracy between poll attempts */
       timeout = device[dn].bjnp_timeout /1000;

backend/plustek-pp_motor.c

@@ -1912,6 +1912,7 @@ static void motorP96SetupRunTable( pScanData ps )
 			    case 3:
 					if (*(p.pb + 2))
 					    bColor = 1;
+                                        // fall through
 			    case 2:
 					if (*(p.pb + 1))
 			    		bColor++;

backend/plustek.c

@@ -1916,6 +1916,7 @@ sane_control_option( SANE_Handle handle, SANE_Int option,
 			case OPT_BUTTON_0:
 				if(!s->calibrating)
 					usb_UpdateButtonStatus(s);
+                                // fall through
 			case OPT_BUTTON_1:
 			case OPT_BUTTON_2:
 			case OPT_BUTTON_3:

backend/plustek_pp.c

@@ -1625,7 +1625,7 @@ SANE_Status sane_control_option( SANE_Handle handle, SANE_Int option,
     					*info |= SANE_INFO_RELOAD_OPTIONS | SANE_INFO_RELOAD_PARAMS;
                 }
 
-           		/* fall through to OPT_HALFTONE */
+                        // fall through
 	    		case OPT_HALFTONE:
 			    	s->val[option].w = optval - s->opt[option].constraint.string_list;
 				    break;

backend/s9036.c

@@ -1022,6 +1022,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	case OPT_BR_Y:
 	  if (info)
 	    *info |= SANE_INFO_RELOAD_PARAMS;
+          // fall through
 	case OPT_BRIGHT_ADJUST:
 	case OPT_CONTR_ADJUST:
 	  s->val[option] = *(SANE_Word *) val;

backend/sharp.c

@@ -2825,6 +2825,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
 	case OPT_BR_Y:
 	  if (info && s->val[option].w != *(SANE_Word *) val)
 	    *info |= SANE_INFO_RELOAD_PARAMS;
+          // fall through
 	case OPT_NUM_OPTS:
 	case OPT_THRESHOLD:
 	  /* xxx theoretically, we could use OPT_THRESHOLD in

backend/sm3600.c

@@ -609,9 +609,10 @@ sane_control_option (SANE_Handle handle, SANE_Int iOpt,
 	{
 	case optResolution:
 	case optTLX: case optTLY: case optBRX: case optBRY:
-	  if (pnInfo) (*pnInfo) |= SANE_INFO_RELOAD_PARAMS;
-	  /* fall through side effect free */
+          if (pnInfo) (*pnInfo) |= SANE_INFO_RELOAD_PARAMS;
+
 #ifdef SM3600_SUPPORT_EXPOSURE
+        // fall through
 	case optBrightness:
 	case optContrast:
 #endif

backend/umax_pp.c

@@ -1462,6 +1462,7 @@ sane_control_option (SANE_Handle handle, SANE_Int option,
           if (info)
             *info |= SANE_INFO_RELOAD_PARAMS;
 
+          // fall through
         case OPT_GRAY_GAIN:
         case OPT_GREEN_GAIN:
         case OPT_RED_GAIN:

backend/umax_pp_low.c

@@ -10239,7 +10239,7 @@ moveToOrigin (void)
       end[0] = 0x19;
       end[1] = 0xD5;
       end[4] = 0x1B;
-
+      // fall through
     case 1220:
     case 2000:
       w = 300;
@@ -11226,6 +11226,7 @@ sanei_umax_pp_startScan (int x, int y, int width, int height, int dpi,
 	  }
       else
 	y += 80;
+      // fall through
     default:
       y += 8;
       break;

frontend/saned.c

@@ -2675,6 +2675,7 @@ saned_avahi_callback (AvahiClient *c, AvahiClientState state, void *userdata)
       case AVAHI_CLIENT_S_COLLISION:
 	DBG (DBG_INFO, "saned_avahi_callback: AVAHI_CLIENT_S_COLLISION\n");
 
+        // fall through
       case AVAHI_CLIENT_S_REGISTERING:
 	DBG (DBG_INFO, "saned_avahi_callback: AVAHI_CLIENT_S_REGISTERING\n");
 	if (avahi_group)

frontend/scanimage.c

@@ -2261,7 +2261,7 @@ main (int argc, char **argv)
 	      printf ("default device is `%s'\n", defdevname);
 	    scanimage_exit (0);
 	  }
-
+          // fall through
 	case 'V':
 	  printf ("scanimage (%s) %s; backend version %d.%d.%d\n", PACKAGE,
 		  VERSION, SANE_VERSION_MAJOR (version_code),

tools/sane-find-scanner.c

@@ -1611,7 +1611,7 @@ main (int argc, char **argv)
 	      usage (0);
 	      exit (0);
 	    }
-
+          // fall through
 	default:
 	  printf ("unknown option: -%c, try -h for help\n", (*ap)[1]);
 	  exit (0);