Compile the source code without the mexFunction first using the -c option (compile only). That will produce an object file. Then compile the other source code that does have the mexFunction and include the object file name on the mex command. E.g., suppose you had two files:
myfunction.f <-- the Fortran source file that contains the mexFunction
myroutines.c <-- the C source that contains routines that myfunction uses
The sequence of mex'ing would be:
mex -c myroutines.c
mex myfunction.f myroutines.obj
The .obj is what you would get on a Windows system. You will get a different object extension on other systems.
On older versions of MATLAB, you will have to use mex -setup prior to the mex calls to make sure the proper compiler is selected.
