Here are some notes from Harry Schaeffer about using C::B to build CalculiX. There is also some history about NASTRAN and some notes about NASTRAN-95. Some of the information here may be useful for building NASTRAN-95 and MYSTRAN.
https://www.mystran.com/misc/Calculix_an...Blocks.pdf
https://www.mystran.com/misc/Calculix_an...Blocks.pdf