components/lwip,esp32: fixes for C++

- put contents of a few headers into c++ guard blocks
- fix off-by-one error in do_global_ctors
- remove system_init from startup code (should be called from main)

components/esp32/cpu_start.c

@@ -134,7 +134,7 @@ void IRAM_ATTR user_start_cpu1(void)
 static void do_global_ctors(void)
 {
     void (**p)(void);
-    for (p = &__init_array_end; p >= &__init_array_start; --p) {
+    for (p = &__init_array_end - 1; p >= &__init_array_start; --p) {
         (*p)();
     }
 }
@@ -153,9 +153,6 @@ void user_start_cpu0(void)
     do_global_ctors();
     esp_ipc_init();
     spi_flash_init();
-#ifdef CONFIG_WIFI_ENABLED
-    system_init();
-#endif
     xTaskCreatePinnedToCore(&mainTask, "mainTask",
             ESP_TASK_MAIN_STACK, NULL,
             ESP_TASK_MAIN_PRIO, NULL, 0);

components/lwip/include/lwip/port/arch/sys_arch.h

@@ -38,6 +38,11 @@
 #include "freertos/queue.h"
 #include "freertos/semphr.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 typedef xSemaphoreHandle sys_sem_t;
 typedef xSemaphoreHandle sys_mutex_t;
 typedef xTaskHandle sys_thread_t;
@@ -67,6 +72,11 @@ uint32_t system_get_time(void);
 void sys_delay_ms(uint32_t ms);
 sys_sem_t* sys_thread_sem_init(void);
 void sys_thread_sem_deinit(void);
-sys_sem_t* sys_thread_sem_get(void);
+sys_sem_t* sys_thread_sem_get(void);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __SYS_ARCH_H__ */
 

components/lwip/include/lwip/port/netif/wlanif.h

@@ -10,6 +10,10 @@
 
 #include "lwip/err.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 err_t wlanif_init(struct netif *netif);
 
 void wlanif_input(struct netif *netif, void *buffer, u16_t len, void* eb);
@@ -20,4 +24,8 @@ wifi_interface_t wifi_get_interface(void *dev);
 
 void netif_reg_addr_change_cb(void* cb);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /*  _WLAN_LWIP_IF_H_ */

components/tcpip_adapter/include/tcpip_adapter.h

@@ -16,9 +16,7 @@
 #define _TCPIP_ADAPTER_H_
 
 #include <stdint.h>
-
 #include "rom/queue.h"
-
 #include "esp_wifi.h"
 
 #define CONFIG_TCPIP_LWIP 1
@@ -28,6 +26,10 @@
 #include "lwip/ip_addr.h"
 #include "apps/dhcpserver.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define IP2STR(ipaddr) ip4_addr1_16(ipaddr), \
     ip4_addr2_16(ipaddr), \
     ip4_addr3_16(ipaddr), \
@@ -129,5 +131,9 @@ wifi_interface_t tcpip_adapter_get_wifi_if(void *dev);
 esp_err_t tcpip_adapter_get_sta_list(struct station_info *sta_info, struct station_list **sta_list);
 esp_err_t tcpip_adapter_free_sta_list(struct station_list *sta_list);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /*  _TCPIP_ADAPTER_H_ */