algorithm.h

// In <algorithm>
// Declare an inline/weak variable.
extern void (*ExtremelyHackyCallThatYouWillNotOverride)()
    __attribute__((weak)) = nullptr;
    
// ...

// Before the sort call
// ...
  if (ExtremelyHackyCallThatYouWillNotOverride)
      ExtremelyHackyCallThatYouWillNotOverride();
  _VSTD::__sort<_Comp_ref>(_VSTD::__unwrap_iter(__first), _VSTD::__unwrap_iter(__last), _Comp_ref(__comp));
// ...

// main.cpp

#include <algorithm>

// Prints the stacktrace.
void backtrace_dumper();

int main(int argc, char** argv) {
  ExtremelyHackyCallThatYouWillNotOverride = &backtrace_dumper;
  return InvokeRealMain(argc, argv);
}