Handle argument conversion in external C structs

[Martin Sjölund]

We need to handle record in external "C" according to the specification:

Each element of the Modelica record is mapped to its corresponding C representation.

Which means we need to convert Integer from long to int.

The elements of the Modelica record class are declared in the same order in the C struct.

Which means we need to create a function to permute the Modelica array since it is in alphabetical ordering.

Arrays cannot be mapped.

Which means the C version of the struct needs to be modified to not contain arrays.