This is blobc. It provides two things:

- A data structure compiler (blobc.py), generating C and Assembly code from
  structure definitions. This is useful to keep such definitions in sync
  between C and Assembly code.

- Python and C# libraries for generating and saving data structure "blobs". These
  blobs are defined in an endian and pointer-size neutral manner and are then
  frozen and saved together with relocation data for pointer fixup given a
  definition of the target machine.

Put together this makes it a convenient toolkit to generate memory-mapped or
data structures for in-place loading.