Temporary header file '/tmp/RrAYBiyB1C/dump1.h' with the following content will be compiled to create GCC translation unit dump:

  // add defines
  #define __STDC_VERSION__ 201710L
#define _FILE_OFFSET_BITS 64
#define _GXX_NULLPTR_T
#define CLUTTER_ENABLE_COMPOSITOR_API 1
#define _REGEX_NELTS(n)
#define _Atomic
#define PACKED

  // add includes
  #include "/usr/include/FLAC++/all.h"
  #include "/usr/include/FLAC++/decoder.h"
  #include "/usr/include/FLAC++/encoder.h"
  #include "/usr/include/FLAC++/export.h"
  #include "/usr/include/FLAC++/metadata.h"

  // add namespaces
  namespace FLAC{typedef int tmp_add_type_1;}
  FLAC::tmp_add_type_1 tmp_add_func_1(){return 0;};
  namespace FLAC{namespace Decoder{typedef int tmp_add_type_2;}}
  FLAC::Decoder::tmp_add_type_2 tmp_add_func_2(){return 0;};
  namespace FLAC{namespace Encoder{typedef int tmp_add_type_3;}}
  FLAC::Encoder::tmp_add_type_3 tmp_add_func_3(){return 0;};
  namespace FLAC{namespace Metadata{typedef int tmp_add_type_4;}}
  FLAC::Metadata::tmp_add_type_4 tmp_add_func_4(){return 0;};
  namespace FLAC{namespace Metadata{namespace local{typedef int tmp_add_type_5;}}}
  FLAC::Metadata::local::tmp_add_type_5 tmp_add_func_5(){return 0;};

  // add classes
  FLAC__StreamMetadata* tmp_add_class_0;
  _G_fpos64_t* tmp_add_class_1;
  _G_fpos_t* tmp_add_class_2;
  _IO_cookie_io_functions_t* tmp_add_class_3;

The GCC parameters:
  gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/RrAYBiyB1C/dump1.h"