Makefile: cppcheck target: Suppress unmatchedSuppression, pass CFLAGS

Some of those warnings don't trigger even on systems with very
similar toolchains, suppress unmatchedSuppression warnings, they're
basically useless.

While at it, pass CFLAGS to cppcheck.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/ndp.c b/ndp.c
index 3a766ec..c04df6a 100644
--- a/ndp.c
+++ b/ndp.c
@@ -140,7 +140,7 @@ int ndp(struct ctx *c, struct ethhdr *eh, size_t len)
 
 		for (n = 0; *c->dns_search[n].n; n++)
 			dns_s_len += strlen(c->dns_search[n].n) + 2;
-		if (len) {
+		if (dns_s_len) {
 			*p++ = 31;			/* DNSSL */
 			*p++ = (len + 8 - 1) / 8 + 1;	/* length */
 			p += 2;				/* reserved */