In the luatex distribution and the repository, there is a toplevel file
called INSTALL. This explains how to build luatex (albeit briefly).
 
I'll try when I have time. I don't have regular acces to the Internet, so I downloaded the source and then read the readme files at home. That is why I hadn't seen the INSTALL. Please, do not believe that the first thing I do is just asking.
 
But that just for your information, the luatex source code is almost
certainly not the cause of luatex's inability to find and load
ec-lmr12.tfm.
 
Not so sure, pdftex generates the format without problem. Anyway, debuggin it will help me find the problem, be it LuaTex fault or mine.
 

Best wishes,
Taco
 
Best wishes to you too