Temporary header file '/tmp/4jgTaD9pUg/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/forms.h"
  #include "/usr/include/flimage.h"

  // add classes
  FL_FORM_* tmp_add_class_0;
  FL_OBJECT_* tmp_add_class_1;
  FL_POPUP_* tmp_add_class_2;
  FL_POPUP_ENTRY_* tmp_add_class_3;
  FL_POPUP_RETURN_* tmp_add_class_4;
  FL_pixmap_* tmp_add_class_5;
  _G_fpos64_t* tmp_add_class_6;
  _G_fpos_t* tmp_add_class_7;
  _IO_cookie_io_functions_t* tmp_add_class_8;
  _XComposeStatus* tmp_add_class_9;
  _XEvent* tmp_add_class_10;
  _XExtData* tmp_add_class_11;
  _XIMHotKeyTrigger* tmp_add_class_12;
  _XIMHotKeyTriggers* tmp_add_class_13;
  _XIMPreeditCaretCallbackStruct* tmp_add_class_14;
  _XIMPreeditDrawCallbackStruct* tmp_add_class_15;
  _XIMPreeditStateNotifyCallbackStruct* tmp_add_class_16;
  _XIMStatusDrawCallbackStruct* tmp_add_class_17;
  _XIMStringConversionCallbackStruct* tmp_add_class_18;
  _XIMStringConversionText* tmp_add_class_19;
  _XIMText* tmp_add_class_20;
  _XImage* tmp_add_class_21;
  flimage_* tmp_add_class_22;
  flimage_marker_* tmp_add_class_23;
  flimage_setup_* tmp_add_class_24;
  flimage_text_* tmp_add_class_25;

The GCC parameters:
  gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/4jgTaD9pUg/dump1.h"