using the library in a memory contained space

[duinamit]

I want to use the multifit_nlin module on a microcontroller - do you have any suggestions on how to approach this?

Most obviously I dont want to link the whole library but rather the least possible amount of this. I have used the library in an application finding a curve fit to given data, now I want to port it into a preexisting nrf-project. I have embedded the include path for the headerfiles but am now thinking about how to add src files/maybe just build an .a file with all the necessary functionalities. The problem is though, I dont know which files to add exactly or if everything is so dependent that I cannot just erase files.
As I said I am basically just doing #include <gsl/gsl_multifit_nlin.h>

any suggestions or experiences with working with GSL on uCs would be appreciated