[Build] Made the autogen.sh script more robust.
[Build] Made the autogen.sh script more robust.

airsim/airinv,jwakely/airinv,jwakely/airinv,airsim/airinv,airsim/airinv,airsim/airinv,airsim/airinv,jwakely/airinv,jwakely/airinv,jwakely/airinv,airsim/airinv,airsim/airinv,jwakely/airinv,jwakely/airinv,jwakely/airinv,airsim/airinv,jwakely/airinv,airsim/airinv