/opt/Espressif/ESP8266_NONOS_SDK/lib/libssl.a(ssl_asn1.o): In function `mktime':
(.text.mktime+0x1c): multiple definition of `mktime'
/opt/Espressif/ESP8266_NONOS_SDK/lib/libc.a(lib_a-mktime.o):/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/newlib-2.0.0/newlib/libc/time/mktime.c:159: first defined here
collect2: error: ld returned 1 exit status
mktime is double defined in libc and libssl:
Using the current ESP8266_NONOS_SDK from github.