lwip menuconfig option for max number of SNTP servers

LWIP has two definess for setting max number of sntp servers:
 - Total number of handled servers
 - max number of sntp's picked via DHCP

by default both values are equal to 1, but could be set separately

Signed-off-by: Emil Muratov <gpm@hotplug.ru>

components/lwip/Kconfig

@@ -837,7 +837,7 @@ menu "LWIP"
 
     menu "SNTP"
 
-        config LWIP_DHCP_MAX_NTP_SERVERS
+        config LWIP_SNTP_MAX_SERVERS
             int "Maximum number of NTP servers"
             default 1
             range 1 16
@@ -846,6 +846,14 @@ menu "LWIP"
                 First argument of sntp_setserver/sntp_setservername functions
                 is limited to this value.
 
+        config LWIP_DHCP_MAX_NTP_SERVERS
+            int "Maximum number of NTP servers aquired via DHCP"
+            default 1
+            range 1 16
+            help
+                Set maximum number of NTP servers aquired via DHCP-offer.
+                Must be less or equal to total "Maximum number of NTP servers".
+
         config LWIP_SNTP_UPDATE_DELAY
             int "Request interval to update time (ms)"
             range 15000 4294967295

components/lwip/port/esp32/include/lwipopts.h

@@ -1074,6 +1074,11 @@ LWIP_FORWARD_DECLARE_C_CXX void sntp_sync_time(struct timeval *tv);
 
 LWIP_FORWARD_DECLARE_C_CXX uint32_t sntp_get_sync_interval(void);
 
+// Max number of SNTP servers handled (default equal to LWIP_DHCP_MAX_NTP_SERVERS)
+#if CONFIG_LWIP_SNTP_MAX_SERVERS_DEFINED && !defined SNTP_MAX_SERVERS
+#define SNTP_MAX_SERVERS                CONFIG_LWIP_SNTP_MAX_SERVERS
+#endif // CONFIG_LWIP_SNTP_MAX_SERVERS_DEFINED
+
 /** Set this to 1 to support DNS names (or IP address strings) to set sntp servers
  * One server address/name can be defined as default if SNTP_SERVER_DNS == 1:
  * \#define SNTP_SERVER_ADDRESS "pool.ntp.org"