Better fallthrough annotation macro.

src/network/net_ne2000.c

@@ -759,9 +759,7 @@ nic_pci_write(UNUSED(int func), int addr, uint8_t val, void *priv)
         case 0x10:       /* PCI_BAR */
             val &= 0xe0; /* 0xe0 acc to RTL DS */
             val |= 0x01; /* re-enable IOIN bit */
-#ifdef FALLTHROUGH_ANNOTATION
-            [[fallthrough]];
-#endif
+            fallthrough;
 
         case 0x11: /* PCI_BAR */
         case 0x12: /* PCI_BAR */

src/network/net_wd8003.c

@@ -735,9 +735,8 @@ wd_init(const device_t *info)
         /* Ethernet, MCA, 5x3 interface chip, RAM 16k */
         case WD8003EA:
             dev->board_chip = WE_ID_SOFT_CONFIG;
-#ifdef FALLTHROUGH_ANNOTATION
-            [[fallthrough]];
-#endif
+            fallthrough;
+
         /* Ethernet, MCA, no interface chip, RAM 16k */
         case WD8003ETA:
             dev->board_chip |= WE_TYPE_WD8013EBT | WE_ID_BUS_MCA;