Temporary header file '/tmp/5iV2RzMh_Z/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/i686-w64-mingw32/include/gcrypt.h" #include "/usr/x86_64-w64-mingw32/include/gcrypt.h" The GCC parameters: gcc -fdump-lang-raw -fkeep-inline-functions -c -x c++ -fpermissive -w "/tmp/5iV2RzMh_Z/dump1.h" -I/usr/x86_64-w64-mingw32/include In file included from /usr/x86_64-w64-mingw32/include/corecrt.h:10, from /usr/x86_64-w64-mingw32/include/stdlib.h:9, from /usr/i686-w64-mingw32/include/gcrypt.h:27, from /tmp/5iV2RzMh_Z/dump1.h:12: /usr/x86_64-w64-mingw32/include/_mingw.h:278:2: error: #error Only Win32 target is supported! 278 | #error Only Win32 target is supported! | ^~~~~ In file included from /usr/x86_64-w64-mingw32/include/stdlib.h:766: /usr/x86_64-w64-mingw32/include/malloc.h:80:10: fatal error: mm_malloc.h: No such file or directory 80 | #include | ^~~~~~~~~~~~~ compilation terminated.