Since SDK 1.01 includes mDNS, this work is now obsolete.
Regarding the compile errors reported, its just SDK version differences, it looks like mem.h needs to be included in the source. Its possible its another include. The original work was done under SDK 093.
For nodemcu, I'm going to wait for them to catch up with SDK 1.01, and then submit a pull request including the hooks for mDNS.
/Kevin