simple question....how to make a gsl_matrix have external linkage?

[John Boik]

Hello.  I have a simple question I hope someone can help me with.  Im still
new to C, and GSL.  I have a gsl matrix that I would like to have file scope
and external linkage.  Also, I will pass an argument to the main function to
tell it how big to make the matrix.  Can anyone tell me how you can declare
a gsl matrix to have file scope and external linkage?  I suppose you could
declare it above main, but it would not know the proper initialization size
at that point.  Thanks.

John Boik