Temporary header file '/tmp/7wD3ym4Q0J/dump1.h' with the following content will be compiled to create GCC translation unit dump:

  // add defines
  #define __STDC_VERSION__ 201710L
#define _GXX_NULLPTR_T
#define CLUTTER_ENABLE_COMPOSITOR_API 1
#define _REGEX_NELTS(n)
#define _Atomic
#define PACKED
#define getaddrinfo_a(a,b,c,d)

  // add includes
  #include "/usr/include/spfft/config.h"
  #include "/usr/include/spfft/errors.h"
  #include "/usr/include/spfft/exceptions.hpp"
  #include "/usr/include/spfft/grid.h"
  #include "/usr/include/spfft/grid.hpp"
  #include "/usr/include/spfft/grid_float.h"
  #include "/usr/include/spfft/grid_float.hpp"
  #include "/usr/include/spfft/multi_transform.h"
  #include "/usr/include/spfft/multi_transform.hpp"
  #include "/usr/include/spfft/multi_transform_float.h"
  #include "/usr/include/spfft/multi_transform_float.hpp"
  #include "/usr/include/spfft/spfft.h"
  #include "/usr/include/spfft/spfft.hpp"
  #include "/usr/include/spfft/spfft_export.h"
  #include "/usr/include/spfft/transform.h"
  #include "/usr/include/spfft/transform.hpp"
  #include "/usr/include/spfft/transform_float.h"
  #include "/usr/include/spfft/transform_float.hpp"
  #include "/usr/include/spfft/types.h"

  // add namespaces
  namespace spfft{typedef int tmp_add_type_1;}
  spfft::tmp_add_type_1 tmp_add_func_1(){return 0;};

The GCC parameters:
  gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/7wD3ym4Q0J/dump1.h"

In file included from /tmp/7wD3ym4Q0J/dump1.h:15:
/usr/include/spfft/grid.h:36:10: fatal error: mpi.h: No such file or directory
   36 | #include <mpi.h>
      |          ^~~~~~~
compilation terminated.