build: allow stricter fallthrough warnings

DPDK currently compiles with implicit-fallthrough=2 warning level. With gcc
-Wextra flag, the default level is 3, so some minor changes are needed to
support this in DPDK.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>

drivers/net/bonding/rte_eth_bond_pmd.c

@@ -2439,7 +2439,8 @@ bond_ethdev_link_update(struct rte_eth_dev *ethdev, int wait_to_complete)
 				bond_ctx->mode4.slave_link.link_autoneg;
 		ethdev->data->dev_link.link_duplex =
 				bond_ctx->mode4.slave_link.link_duplex;
-		/* fall through to update link speed */
+		/* fall through */
+		/* to update link speed */
 	case BONDING_MODE_ROUND_ROBIN:
 	case BONDING_MODE_BALANCE:
 	case BONDING_MODE_TLB:

drivers/net/fm10k/base/meson.build

@@ -12,7 +12,8 @@ sources = [
 
 error_cflags = ['-Wno-unused-parameter', '-Wno-unused-value',
 	'-Wno-strict-aliasing', '-Wno-format-extra-args',
-	'-Wno-unused-variable', '-Wno-missing-field-initializers'
+	'-Wno-unused-variable', '-Wno-missing-field-initializers',
+	'-Wno-implicit-fallthrough'
 ]
 c_args = cflags
 if allow_experimental_apis

lib/librte_cmdline/cmdline_parse_num.c

@@ -196,7 +196,7 @@ cmdline_parse_num(cmdline_parse_token_hdr_t *tk, const char *srcbuf, void *res,
 
 		case HEX:
 			st = HEX_OK;
-			/* fall-through no break */
+			/* fall-through */
 		case HEX_OK:
 			if (c >= '0' && c <= '9') {
 				if (add_to_res(c - '0', &res1, 16) < 0)