Better fallthrough annotation macro.

src/sound/snd_ac97_codec.c

@@ -418,9 +418,7 @@ rate:              /* Writable only if VRA/VRM is set. */
                 /* Get actual previous value. */
                 prev = dev->vendor_reg_pages[(i << 3) | ((reg & 0x0e) >> 1)];
             }
-#ifdef FALLTHROUGH_ANNOTATION
-            [[fallthrough]];
-#endif
+            fallthrough;
 
         case 0x5a ... 0x5e: /* Vendor Reserved */
         case 0x70 ... 0x7a:

src/sound/snd_ad1848.c

@@ -242,9 +242,7 @@ ad1848_write(uint16_t addr, uint8_t val, void *priv)
                 case 10:
                     if (ad1848->type < AD1848_TYPE_CS4235)
                         break;
-#ifdef FALLTHROUGH_ANNOTATION
-                    [[fallthrough]];
-#endif
+                    fallthrough;
 
                 case 8:
                     updatefreq = 1;

src/sound/snd_cmi8x38.c

@@ -469,9 +469,7 @@ cmi8x38_sb_mixer_write(uint16_t addr, uint8_t val, void *priv)
             case 0xf8 ... 0xff:
                 if (dev->type == CMEDIA_CMI8338)
                     mixer->regs[mixer->index] = val;
-#ifdef FALLTHROUGH_ANNOTATION
-                [[fallthrough]];
-#endif
+                fallthrough;
 
             case 0xf1 ... 0xf7:
                 return;

src/sound/snd_cs423x.c

@@ -300,9 +300,7 @@ cs423x_write(uint16_t addr, uint8_t val, void *priv)
                     switch (val) {
                         case 0x55: /* Disable PnP Key */
                             dev->pnp_enable = 0;
-#ifdef FALLTHROUGH_ANNOTATION
-                            [[fallthrough]];
-#endif
+                            fallthrough;
 
                         case 0x5a: /* Update Hardware Configuration Data */
                             cs423x_pnp_enable(dev, 0, 1);

src/sound/snd_gus.c

@@ -643,9 +643,7 @@ writegus(uint16_t addr, uint8_t val, void *priv)
                 else if (gus->irq != -1)
                     picint(1 << gus->irq);
             }
-#ifdef FALLTHROUGH_ANNOTATION
-            [[fallthrough]];
-#endif
+            fallthrough;
         case 0x20d:
             gus->sb_2xc = val;
             break;

src/sound/snd_sb_dsp.c

@@ -601,9 +601,7 @@ sb_exec_command(sb_dsp_t *dsp)
         case 0x75: /* 4-bit ADPCM output with reference */
             dsp->sbref  = dsp->dma_readb(dsp->dma_priv);
             dsp->sbstep = 0;
-#ifdef FALLTHROUGH_ANNOTATION
-            [[fallthrough]];
-#endif
+            fallthrough;
         case 0x74: /* 4-bit ADPCM output */
             sb_start_dma(dsp, 1, 0, ADPCM_4, dsp->sb_data[0] + (dsp->sb_data[1] << 8));
             dsp->sbdat2 = dsp->dma_readb(dsp->dma_priv);