Fix #1481 - use stricter compilation flags

src/dns.h

@@ -36,4 +36,3 @@ void mg_resolve_cancel(struct mg_connection *);
 bool mg_dns_parse(const uint8_t *buf, size_t len, struct mg_dns_message *);
 size_t mg_dns_parse_rr(const uint8_t *buf, size_t len, size_t ofs,
                        bool is_question, struct mg_dns_rr *);
-size_t mg_dns_decode_name(const uint8_t *, size_t, size_t, char *, size_t);

src/fs_packed.c

@@ -9,6 +9,7 @@ struct packed_file {
 
 const char *mg_unpack(const char *path, size_t *size, time_t *mtime);
 const char *mg_unlist(size_t no);
+
 #if MG_ENABLE_PACKED_FS
 #else
 const char *mg_unpack(const char *path, size_t *size, time_t *mtime) {

src/str.h

@@ -41,3 +41,4 @@ size_t mg_asprintf(char **, size_t, const char *fmt, ...) PRINTF_LIKE(3, 4);
 size_t mg_vasprintf(char **buf, size_t size, const char *fmt, va_list ap);
 int mg_check_ip_acl(struct mg_str acl, uint32_t remote_ip);
 int64_t mg_to64(struct mg_str str);
+size_t mg_lld(char *buf, int64_t val, bool is_signed, bool is_hex);