Temporary header file '/tmp/gEA8QpzuHJ/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
#define getaddrinfo_a(a,b,c,d)

  // add includes
  #include "/usr/include/matroska/FileKax.h"
  #include "/usr/include/matroska/KaxAttached.h"
  #include "/usr/include/matroska/KaxAttachments.h"
  #include "/usr/include/matroska/KaxBlock.h"
  #include "/usr/include/matroska/KaxBlockData.h"
  #include "/usr/include/matroska/KaxChapters.h"
  #include "/usr/include/matroska/KaxCluster.h"
  #include "/usr/include/matroska/KaxClusterData.h"
  #include "/usr/include/matroska/KaxConfig.h"
  #include "/usr/include/matroska/KaxContentEncoding.h"
  #include "/usr/include/matroska/KaxContexts.h"
  #include "/usr/include/matroska/KaxCues.h"
  #include "/usr/include/matroska/KaxCuesData.h"
  #include "/usr/include/matroska/KaxDefines.h"
  #include "/usr/include/matroska/KaxInfo.h"
  #include "/usr/include/matroska/KaxInfoData.h"
  #include "/usr/include/matroska/KaxSeekHead.h"
  #include "/usr/include/matroska/KaxSegment.h"
  #include "/usr/include/matroska/KaxSemantic.h"
  #include "/usr/include/matroska/KaxTag.h"
  #include "/usr/include/matroska/KaxTags.h"
  #include "/usr/include/matroska/KaxTrackAudio.h"
  #include "/usr/include/matroska/KaxTrackEntryData.h"
  #include "/usr/include/matroska/KaxTrackVideo.h"
  #include "/usr/include/matroska/KaxTracks.h"
  #include "/usr/include/matroska/KaxTypes.h"
  #include "/usr/include/matroska/KaxVersion.h"
  #include "/usr/include/matroska/c/libmatroska.h"
  #include "/usr/include/matroska/c/libmatroska_t.h"
  #include "/usr/include/matroska/matroska_export.h"

  // add namespaces
  namespace libebml{typedef int tmp_add_type_1;}
  libebml::tmp_add_type_1 tmp_add_func_1(){return 0;};
  namespace libmatroska{typedef int tmp_add_type_2;}
  libmatroska::tmp_add_type_2 tmp_add_func_2(){return 0;};

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

The GCC parameters:
  gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/gEA8QpzuHJ/dump1.h"