The mqttc demo under example path can not support mbedtls api.
Because of the MQTT-C source code already contains many types of
link examples, so we added the corresponding makefile to
support mbedtls mqttc connections publisher and posix mqttc
connections publisher and subscriber.
Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>
This option, which resolves to -w when CONFIG_CYGWIN_WINTOOL is
configured, is now appended to INCDIR in tools/Config.mk.
See git commit # 5eae32577e5d5226e5d3027c169eeb369f83f77d in the main
