I am not sure whether matgdns.c is what you need, but you can achieve this using coder.read and coder.write
In short, coder.write(fileName,data) stores the argument data in a file with the name fileName.coderdata in your current directory. You can use this function in your host machine to sae the paraleters in a file.
dataFromFile = coder.read(fileName) reads from the fileName.coderdata storage file and returns the data stored within the file. You can use this function in your MATLAB® code for which you want to generate C/C++ code. The generated code performs the data read at run time.