Actually can contribute an answer for once ... so thought would share
After the m_fcompxe_2016.2.049.dmg update in February the IFORT plugin was working in my Xcode 7.2 setup, yay happy days
Upgrade to Xcode 7.3 came out couple of weeks ago, IFORT plugin went away, sadness
Tried repair and other options from the .dmg ... but still no Fortran rules in Xcode.
Finally found this and now have IFORT working in latest Xcode again
> pwd
/Library/Application Support/Developer
> ls -l
drwxr-xr-x 3 7795 wheel 102 Feb 18 13:18 7.2
> sudo cp -pr 7.2 7.3
> ls -l
drwxr-xr-x 3 7795 wheel 102 Feb 18 13:18 7.2
drwxr-xr-x 3 7795 wheel 102 Feb 18 13:18 7.3
restarted Xcode and have Fortran build rules again