Temporary header file '/tmp/oJ4FGdhTl1/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
#ifdef __cplusplus
// C17 compat layer
#define _Alignof(type) alignof(type)
#endif
#define getaddrinfo_a(a,b,c,d)

  // add includes
  #include "/usr/include/sdformat-12.3/sdf/Actor.hh"
  #include "/usr/include/sdformat-12.3/sdf/AirPressure.hh"
  #include "/usr/include/sdformat-12.3/sdf/Altimeter.hh"
  #include "/usr/include/sdformat-12.3/sdf/Assert.hh"
  #include "/usr/include/sdformat-12.3/sdf/Atmosphere.hh"
  #include "/usr/include/sdformat-12.3/sdf/Box.hh"
  #include "/usr/include/sdformat-12.3/sdf/Camera.hh"
  #include "/usr/include/sdformat-12.3/sdf/Capsule.hh"
  #include "/usr/include/sdformat-12.3/sdf/Collision.hh"
  #include "/usr/include/sdformat-12.3/sdf/Console.hh"
  #include "/usr/include/sdformat-12.3/sdf/Cylinder.hh"
  #include "/usr/include/sdformat-12.3/sdf/Element.hh"
  #include "/usr/include/sdformat-12.3/sdf/Ellipsoid.hh"
  #include "/usr/include/sdformat-12.3/sdf/Error.hh"
  #include "/usr/include/sdformat-12.3/sdf/Exception.hh"
  #include "/usr/include/sdformat-12.3/sdf/Filesystem.hh"
  #include "/usr/include/sdformat-12.3/sdf/ForceTorque.hh"
  #include "/usr/include/sdformat-12.3/sdf/Frame.hh"
  #include "/usr/include/sdformat-12.3/sdf/Geometry.hh"
  #include "/usr/include/sdformat-12.3/sdf/Gui.hh"
  #include "/usr/include/sdformat-12.3/sdf/Heightmap.hh"
  #include "/usr/include/sdformat-12.3/sdf/Imu.hh"
  #include "/usr/include/sdformat-12.3/sdf/InterfaceElements.hh"
  #include "/usr/include/sdformat-12.3/sdf/InterfaceFrame.hh"
  #include "/usr/include/sdformat-12.3/sdf/InterfaceJoint.hh"
  #include "/usr/include/sdformat-12.3/sdf/InterfaceLink.hh"
  #include "/usr/include/sdformat-12.3/sdf/InterfaceModel.hh"
  #include "/usr/include/sdformat-12.3/sdf/InterfaceModelPoseGraph.hh"
  #include "/usr/include/sdformat-12.3/sdf/Joint.hh"
  #include "/usr/include/sdformat-12.3/sdf/JointAxis.hh"
  #include "/usr/include/sdformat-12.3/sdf/Lidar.hh"
  #include "/usr/include/sdformat-12.3/sdf/Light.hh"
  #include "/usr/include/sdformat-12.3/sdf/Link.hh"
  #include "/usr/include/sdformat-12.3/sdf/Magnetometer.hh"
  #include "/usr/include/sdformat-12.3/sdf/Material.hh"
  #include "/usr/include/sdformat-12.3/sdf/Mesh.hh"
  #include "/usr/include/sdformat-12.3/sdf/Model.hh"
  #include "/usr/include/sdformat-12.3/sdf/NavSat.hh"
  #include "/usr/include/sdformat-12.3/sdf/Noise.hh"
  #include "/usr/include/sdformat-12.3/sdf/Param.hh"
  #include "/usr/include/sdformat-12.3/sdf/ParserConfig.hh"
  #include "/usr/include/sdformat-12.3/sdf/ParticleEmitter.hh"
  #include "/usr/include/sdformat-12.3/sdf/Pbr.hh"
  #include "/usr/include/sdformat-12.3/sdf/Physics.hh"
  #include "/usr/include/sdformat-12.3/sdf/Plane.hh"
  #include "/usr/include/sdformat-12.3/sdf/PrintConfig.hh"
  #include "/usr/include/sdformat-12.3/sdf/Root.hh"
  #include "/usr/include/sdformat-12.3/sdf/SDFImpl.hh"
  #include "/usr/include/sdformat-12.3/sdf/Scene.hh"
  #include "/usr/include/sdformat-12.3/sdf/SemanticPose.hh"
  #include "/usr/include/sdformat-12.3/sdf/Sensor.hh"
  #include "/usr/include/sdformat-12.3/sdf/Sky.hh"
  #include "/usr/include/sdformat-12.3/sdf/Sphere.hh"
  #include "/usr/include/sdformat-12.3/sdf/Surface.hh"
  #include "/usr/include/sdformat-12.3/sdf/Types.hh"
  #include "/usr/include/sdformat-12.3/sdf/Visual.hh"
  #include "/usr/include/sdformat-12.3/sdf/World.hh"
  #include "/usr/include/sdformat-12.3/sdf/parser.hh"
  #include "/usr/include/sdformat-12.3/sdf/sdf.hh"
  #include "/usr/include/sdformat-12.3/sdf/sdf_config.h"
  #include "/usr/include/sdformat-12.3/sdf/system_util.hh"

  // add namespaces
  namespace ignition{typedef int tmp_add_type_1;}
  ignition::tmp_add_type_1 tmp_add_func_1(){return 0;};
  namespace ignition{namespace math{typedef int tmp_add_type_2;}}
  ignition::math::tmp_add_type_2 tmp_add_func_2(){return 0;};
  namespace ignition{namespace math{namespace v6{typedef int tmp_add_type_3;}}}
  ignition::math::v6::tmp_add_type_3 tmp_add_func_3(){return 0;};
  namespace ignition{namespace math{namespace v6{namespace graph{typedef int tmp_add_type_4;}}}}
  ignition::math::v6::graph::tmp_add_type_4 tmp_add_func_4(){return 0;};
  namespace ignition{namespace utils{typedef int tmp_add_type_5;}}
  ignition::utils::tmp_add_type_5 tmp_add_func_5(){return 0;};
  namespace ignition{namespace utils{namespace detail{typedef int tmp_add_type_6;}}}
  ignition::utils::detail::tmp_add_type_6 tmp_add_func_6(){return 0;};
  namespace sdf{typedef int tmp_add_type_7;}
  sdf::tmp_add_type_7 tmp_add_func_7(){return 0;};
  namespace sdf{namespace v12{typedef int tmp_add_type_8;}}
  sdf::v12::tmp_add_type_8 tmp_add_func_8(){return 0;};
  namespace sdf{namespace v12{namespace filesystem{typedef int tmp_add_type_9;}}}
  sdf::v12::filesystem::tmp_add_type_9 tmp_add_func_9(){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/oJ4FGdhTl1/dump1.h"  -I/usr/include/sdformat-12.3 -I/usr/include/ignition/utils1 -I/usr/include/ignition/math6