ESP8266 Community Forum

I use cygwin on Windows 7, and xtensa-lx106-elf to compile the firmware.
Everything goes smooth until the last step, it always produce in the cmd:

D:/Documents/GitHub/esp8266-wiki/sdk/esp_iot_sdk_v0.9.5/lib\libssl.a<ssl_loader.o>: In function 'ssl_obj_free':
<.irom0.text+0x4c0>: undefined reference to 'default_private_key'
D:/Documents/GitHub/esp8266-wiki/sdk/esp_iot_sdk_v0.9.5/lib\libssl.a<ssl_loader.o>: In function 'ssl_obj_free':
<.irom0.text+0x4c4>: undefined reference to 'default_private_key_len'
D:/Documents/GitHub/esp8266-wiki/sdk/esp_iot_sdk_v0.9.5/lib\libssl.a<ssl_loader.o>: In function 'ssl_obj_free':
<.irom0.text+0x4c8>: undefined reference to 'default_certificate_len'
D:/Documents/GitHub/esp8266-wiki/sdk/esp_iot_sdk_v0.9.5/lib\libssl.a<ssl_loader.o>: In function 'ssl_obj_free':
<.irom0.text+0x4cc>: undefined reference to 'default_certificate'

I tried using updated SDK like v1.0.0 or so, it still doesn't work.
Can anyone tell me what's going on?
Thank you very much.