I have provided you the Reason why you were getting compilation error, when you modify "HttpExampleClient" project below,
In "HttpExampleClient" project Makefile,Only Certain Feature Set like WLAN, HTTPRESTCLIENT were Enabled. Sensor Feature was not Enabled.
#Below settings are done for optimized build.Unused common code is disabled to reduce the build time
#Enabled feature macros for common code
Since Sensor Feature was not Enabled, In "SDK\xdk110\Common\source\Sensor\Sensor.c" file, "XDK_SENSOR_SENSOR" value would be 0. "Sensor_GetData API" in that file will not be referenced. So you were getting compilation error.
Since I have created New XDK C Project, In "HTTPTestProject" project Makefile, XDK_FEATURE_SET ='ALL'. It means all the features like WLAN, BLE, Sensor, etc will be enabled.