Temporary header file '/tmp/3wi5giJJ5N/dump1.h' with the following content will be compiled to create GCC translation unit dump:

  // add defines
  #define __STDC_VERSION__ 201710L
#define _TIME_BITS 64
#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/dmtx.h"

  // add classes
  DmtxBestLine_struct* tmp_add_class_0;
  DmtxByteList_struct* tmp_add_class_1;
  DmtxChannelGroup_struct* tmp_add_class_2;
  DmtxChannel_struct* tmp_add_class_3;
  DmtxDecode_struct* tmp_add_class_4;
  DmtxEncodeStream_struct* tmp_add_class_5;
  DmtxEncode_struct* tmp_add_class_6;
  DmtxImage_struct* tmp_add_class_7;
  DmtxMessage_struct* tmp_add_class_8;
  DmtxPixelLoc_struct* tmp_add_class_9;
  DmtxPointFlow_struct* tmp_add_class_10;
  DmtxQuadruplet_struct* tmp_add_class_11;
  DmtxRay2_struct* tmp_add_class_12;
  DmtxRegion_struct* tmp_add_class_13;
  DmtxScanGrid_struct* tmp_add_class_14;
  DmtxTime_struct* tmp_add_class_15;
  DmtxTriplet_struct* tmp_add_class_16;
  DmtxVector2_struct* tmp_add_class_17;

The GCC parameters:
  gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/3wi5giJJ5N/dump1.h"