tree-wide: use our memset() macros instead of memset() itself

src/test/test-pty.c

@@ -100,7 +100,7 @@ static void test_pty(void) {
         Pty *pty;
 
         rcvsiz = 0;
-        memset(rcvbuf, 0, sizeof(rcvbuf));
+        zero(rcvbuf);
 
         assert_se(sd_event_default(&event) >= 0);
 

src/test/test-ring.c

@@ -36,7 +36,7 @@ static void test_ring(void) {
         struct iovec vec[2];
         int s;
 
-        memset(&r, 0, sizeof(r));
+        zero(r);
 
         l = ring_peek(&r, vec);
         assert_se(l == 0);