added missing includes in new cdo_fftw files

src/cdo_fftw3.cc

 #include "cdo_fftw3.h"
+
+#include <mutex>
+
+#include "cdo_options.h"
+#include "cimdOmp.h"
+#include <cdi.h>
+#ifdef HAVE_LIBFFTW3
+static std::mutex fftwMutex;
+#endif
+
 #ifdef HAVE_LIBFFTW3
 void
 fourier2grid(int gridID1, const Varray<double> &array1, Varray<double> &array2)

src/cdo_fftw3.h

 #ifndef CDO_FFTW3_H
 #define CDO_FFTW3_H
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "varray.h"
 
+
 void
 fourier2grid(int gridID1, const Varray<double> &array1, Varray<double> &array2);