Update socket_driver.c
commented out unused static var declarations (bind_a, getsockname_a,  recvfrom_a) because otherwise it won't be comilable using esp-idf 3.2 which defines -Werror=unused-const-variable - i did not delete because i feel there is missing some code which should use these vars.
@@ -47,10 +47,12 @@ static const char *const proto_udp_a = "\x3" "udp";
static const char *const proto_tcp_a = "\x3" "tcp";
static const char *const socket_a = "\x6" "socket";
static const char *const fcntl_a = "\x5" "fcntl";
-static const char *const bind_a = "\x4" "bind";
-static const char *const getsockname_a = "\xB" "getsockname";
+
+// 3 unused variables -> won't compile using esp-idf v 3.2
+// static const char *const bind_a = "\x4" "bind";
+// static const char *const getsockname_a = "\xB" "getsockname";
+// static const char *const recvfrom_a = "\x8" "recvfrom";
static const char *const sendto_a = "\x6" "sendto";
-static const char *const recvfrom_a = "\x8" "recvfrom";
// TODO use net_conn instead of BSD Sockets
