Extend source files to store a file hash

[cdacamar]

There is a need to associate with every source file, a hash of its contents. We would like an IFC structure for that information. The MSVC compiler can workaround the lack of such structure with the following set up in IFC-43 using an MSVC-specific trait.

What is the IFC specification for that in general, independent of the toolset producing the IFC file?