Fix FMU hybrj_ function signature

3rdParty/CMinpack/hybrj_.c has void return value, FMU export uses int.

EMCC linking and WebAssembly runtime errors out on incorrect function signature.

Belonging to [master]:
  - #2806

SimulationRuntime/c/simulation/solver/nonlinearSolverHybrd.c

@@ -56,7 +56,7 @@ struct dataAndSys {
   int sysNumber;
 };
 
-static int wrapper_fvec_hybrj(const integer* n, const double* x, double* f, double* fjac, const integer* ldjac, const integer* iflag, void* data);
+static void wrapper_fvec_hybrj(const integer* n, const double* x, double* f, double* fjac, const integer* ldjac, const integer* iflag, void* data);
 
 /*! \fn allocate memory for nonlinear system solver hybrd
  *
@@ -305,7 +305,7 @@ static int getAnalyticalJacobian(struct dataAndSys* dataSys, double* jac)
  *
  *
  */
-static int wrapper_fvec_hybrj(const integer* n, const double* x, double* f, double* fjac, const integer* ldjac, const integer* iflag, void* dataAndSysNum)
+static void wrapper_fvec_hybrj(const integer* n, const double* x, double* f, double* fjac, const integer* ldjac, const integer* iflag, void* dataAndSysNum)
 {
   int i,j;
   struct dataAndSys *dataSys = (struct dataAndSys*) dataAndSysNum;
@@ -400,8 +400,6 @@ static int wrapper_fvec_hybrj(const integer* n, const double* x, double* f, doub
     throwStreamPrint(NULL, "Well, this is embarrasing. The non-linear solver should never call this case.%d", (int)*iflag);
     break;
   }
-
-  return 0;
 }
 
 /*! \fn solve non-linear system with hybrd method

SimulationRuntime/c/simulation/solver/nonlinearSolverHybrd.h

@@ -45,7 +45,7 @@ extern "C" {
 #endif
 
 extern
-int hybrj_( int(*) (const integer*, const double*, double*, double *, const integer*, const integer*, void*),  const integer *n, double *x, double *fvec, double *fjac, const integer *ldfjac,
+void hybrj_( void(*) (const integer*, const double*, double*, double *, const integer*, const integer*, void*),  const integer *n, double *x, double *fvec, double *fjac, const integer *ldfjac,
   const double *xtol, const integer *axfev, double *diag, const integer *mode,
   const double *factor, const integer *nprint, integer *info, integer *nfev, integer *njev,
   double *r, integer *lr, double *qtf, double *wa1, double *wa2,