Compiling under Windows 10 with MinGW gcc/gfortran 8.1.0

Hi,

I am using GNU Fortran (x86_64-posix-sjlj-rev0, Built by MinGW-W64 project) 8.1.0
I got an error regarding CalculiX.h:

```
D:/00master/ccx_2.17/src/include/CalculiX.h:74:25: error: expected ')' before '(' token
 void FORTRAN(actideacti,(char *set,ITG *nset,ITG *istartset,ITG *iendset,
                         ^
                         )
```
How to solve this?

Regards,

Cean