Indicate that some variables are not read later in the function

Reported by:	clang-scan

tar/multitape/multitape_metadata.c

@@ -269,6 +269,8 @@ multitape_metadata_dec(struct tapemetadata * mdat, uint8_t * buf,
 	buflen -= 256;
 	p += 256;
 
+	(void)p; /* p is not used beyond this point. */
+
 	/* We should be at the end of the metadata now. */
 	if (buflen != 0)
 		goto bad2;

tar/multitape/multitape_metaindex.c

@@ -106,6 +106,8 @@ multitape_metaindex_put(STORAGE_W * S, CHUNKS_W * C,
 		memcpy(p, mind->tindex, mind->tindexlen);
 	p += mind->tindexlen;
 
+	(void)p; /* p is not used beyond this point. */
+
 	/* Compute hash of tape name. */
 	if (crypto_hash_data(CRYPTO_KEY_HMAC_NAME,
 	    (uint8_t *)mdat->name, strlen(mdat->name), hbuf))
@@ -273,6 +275,8 @@ multitape_metaindex_get(STORAGE_R * S, CHUNKS_S * C,
 	if (buflen != 0)
 		goto corrupt3;
 
+	(void)buf; /* buf is not used beyond this point. */
+
 	/* Free metaindex buffer. */
 	free(mbuf);
 

tests/valgrind/potential-memleaks.c

@@ -56,6 +56,8 @@ pl_freebsd_getpwuid(void)
 		exit(1);
 	}
 
+	(void)pwd; /* pwd is not used beyond this point. */
+
 	/* POSIX says that we *shall not* free `pwd`. */
 }