[wpiutil] StackTrace: Add ability to override default implementation (#3951)

wpiutil/src/main/native/cpp/StackTraceWrap.cpp

@@ -0,0 +1,18 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include <atomic>
+
+#include "wpi/StackTrace.h"
+
+static std::atomic<std::string (*)(int offset)> gStackTraceImpl{
+    wpi::GetStackTraceDefault};
+
+std::string wpi::GetStackTrace(int offset) {
+  return (gStackTraceImpl.load())(offset);
+}
+
+void wpi::SetGetStackTraceImpl(std::string (*func)(int offset)) {
+  gStackTraceImpl = func ? func : wpi::GetStackTraceDefault;
+}