The Fortran code needs the ISO C binding annotations to be callable
from Rust using the C ABI. The Fortran project is built as an
external submodule to minimise the dependence of the two projects.
The build script defines invokes cmake
and specifies
the linker options to link to the Fortran shared library.
When a file input is received, we can use the shared ram disk
available to all users on /dev/shm
. Just creating a job specific
working directory, and writing any intermediate files should be
sufficient for the first iteration.