int tcc_backtrace(const char*, ...);#define hello() \    tcc_backtrace("hello from %s() / %s:%d",__FUNCTION__,__FILE__,__LINE__) #ifndef _WIN32# define __declspec(n)#endif #if DLL==1__declspec(dllexport) int f_1(){    hello();    return 0;}  #elif DLL==2__declspec(dllexport) int f_2(){    hello();    return 0;}  #else int f_1();int f_2();int f_main(){    hello();    return 0;} int main (){    f_1();    f_2();    f_main();    return 0;} #endif