Fix valgrind test

Makefile

@@ -33,7 +33,7 @@ CFLAGS  += -DMG_ENABLE_OPENSSL=1 -I$(OPENSSL)/include
 LDFLAGS ?= -L$(OPENSSL)/lib -lssl -lcrypto
 endif
 
-all: mg_prefix unamalgamated unpacked test test++ arm examples vc98 vc2017 mingw mingw++ linux linux++ fuzz
+all: mg_prefix unamalgamated unpacked test test++ valgrind arm examples vc98 vc2017 mingw mingw++ linux linux++ fuzz
 
 examples:
 	@for X in $(EXAMPLES); do test -f $$X/Makefile || continue; $(MAKE) -C $$X example || exit 1; done

mongoose.c

@@ -3497,6 +3497,7 @@ void mg_connect_resolved(struct mg_connection *c) {
 static SOCKET raccept(SOCKET sock, union usa *usa, socklen_t len) {
   SOCKET s = INVALID_SOCKET;
   do {
+    memset(usa, 0, sizeof(*usa));
     s = accept(sock, &usa->sa, &len);
   } while (s == INVALID_SOCKET && errno == EINTR);
   return s;

src/sock.c

@@ -361,6 +361,7 @@ void mg_connect_resolved(struct mg_connection *c) {
 static SOCKET raccept(SOCKET sock, union usa *usa, socklen_t len) {
   SOCKET s = INVALID_SOCKET;
   do {
+    memset(usa, 0, sizeof(*usa));
     s = accept(sock, &usa->sa, &len);
   } while (s == INVALID_SOCKET && errno == EINTR);
   return s;