Temporary header file '/tmp/UaKopq07O3/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/nlohmann/detail/macro_unscope.hpp"
  #include "/usr/include/nlohmann/thirdparty/hedley/hedley.hpp"
  #include "/usr/include/nlohmann/adl_serializer.hpp"
  #include "/usr/include/nlohmann/byte_container_with_subtype.hpp"
  #include "/usr/include/nlohmann/detail/abi_macros.hpp"
  #include "/usr/include/nlohmann/detail/conversions/from_json.hpp"
  #include "/usr/include/nlohmann/detail/conversions/to_chars.hpp"
  #include "/usr/include/nlohmann/detail/conversions/to_json.hpp"
  #include "/usr/include/nlohmann/detail/exceptions.hpp"
  #include "/usr/include/nlohmann/detail/hash.hpp"
  #include "/usr/include/nlohmann/detail/input/binary_reader.hpp"
  #include "/usr/include/nlohmann/detail/input/input_adapters.hpp"
  #include "/usr/include/nlohmann/detail/input/json_sax.hpp"
  #include "/usr/include/nlohmann/detail/input/lexer.hpp"
  #include "/usr/include/nlohmann/detail/input/parser.hpp"
  #include "/usr/include/nlohmann/detail/input/position_t.hpp"
  #include "/usr/include/nlohmann/detail/iterators/internal_iterator.hpp"
  #include "/usr/include/nlohmann/detail/iterators/iter_impl.hpp"
  #include "/usr/include/nlohmann/detail/iterators/iteration_proxy.hpp"
  #include "/usr/include/nlohmann/detail/iterators/iterator_traits.hpp"
  #include "/usr/include/nlohmann/detail/iterators/json_reverse_iterator.hpp"
  #include "/usr/include/nlohmann/detail/iterators/primitive_iterator.hpp"
  #include "/usr/include/nlohmann/detail/json_pointer.hpp"
  #include "/usr/include/nlohmann/detail/json_ref.hpp"
  #include "/usr/include/nlohmann/detail/macro_scope.hpp"
  #include "/usr/include/nlohmann/detail/meta/call_std/begin.hpp"
  #include "/usr/include/nlohmann/detail/meta/call_std/end.hpp"
  #include "/usr/include/nlohmann/detail/meta/cpp_future.hpp"
  #include "/usr/include/nlohmann/detail/meta/detected.hpp"
  #include "/usr/include/nlohmann/detail/meta/identity_tag.hpp"
  #include "/usr/include/nlohmann/detail/meta/is_sax.hpp"
  #include "/usr/include/nlohmann/detail/meta/std_fs.hpp"
  #include "/usr/include/nlohmann/detail/meta/type_traits.hpp"
  #include "/usr/include/nlohmann/detail/meta/void_t.hpp"
  #include "/usr/include/nlohmann/detail/output/binary_writer.hpp"
  #include "/usr/include/nlohmann/detail/output/output_adapters.hpp"
  #include "/usr/include/nlohmann/detail/output/serializer.hpp"
  #include "/usr/include/nlohmann/detail/string_concat.hpp"
  #include "/usr/include/nlohmann/detail/string_escape.hpp"
  #include "/usr/include/nlohmann/detail/value_t.hpp"
  #include "/usr/include/nlohmann/json.hpp"
  #include "/usr/include/nlohmann/json_fwd.hpp"
  #include "/usr/include/nlohmann/ordered_map.hpp"
  #include "/usr/include/nlohmann/thirdparty/hedley/hedley_undef.hpp"

  // add namespaces
  namespace nlohmann{typedef int tmp_add_type_1;}
  nlohmann::tmp_add_type_1 tmp_add_func_1(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{typedef int tmp_add_type_2;}}
  nlohmann::json_abi_v3_11_2::tmp_add_type_2 tmp_add_func_2(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace detail{typedef int tmp_add_type_3;}}}
  nlohmann::json_abi_v3_11_2::detail::tmp_add_type_3 tmp_add_func_3(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace detail2{typedef int tmp_add_type_4;}}}
  nlohmann::json_abi_v3_11_2::detail2::tmp_add_type_4 tmp_add_func_4(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace detail{namespace container_input_adapter_factory_impl{typedef int tmp_add_type_5;}}}}
  nlohmann::json_abi_v3_11_2::detail::container_input_adapter_factory_impl::tmp_add_type_5 tmp_add_func_5(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace detail{namespace dtoa_impl{typedef int tmp_add_type_6;}}}}
  nlohmann::json_abi_v3_11_2::detail::dtoa_impl::tmp_add_type_6 tmp_add_func_6(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace detail{namespace impl{typedef int tmp_add_type_7;}}}}
  nlohmann::json_abi_v3_11_2::detail::impl::tmp_add_type_7 tmp_add_func_7(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace literals{typedef int tmp_add_type_8;}}}
  nlohmann::json_abi_v3_11_2::literals::tmp_add_type_8 tmp_add_func_8(){return 0;};
  namespace nlohmann{namespace json_abi_v3_11_2{namespace literals{namespace json_literals{typedef int tmp_add_type_9;}}}}
  nlohmann::json_abi_v3_11_2::literals::json_literals::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/UaKopq07O3/dump1.h"