Make RUNTIME_ASSERT have more useful output in debug mode

src/base/logging.cc

Index: src/base/logging.cc
diff --git a/src/base/logging.cc b/src/base/logging.cc
index a2688c9c9aefb1f566f048e79c7f6ec4c0f9db16..ebab129f93630eac5d6f54b2ee16a709928f91ea 100644
--- a/src/base/logging.cc
+++ b/src/base/logging.cc
@@ -115,3 +115,14 @@ extern "C" void V8_Fatal(const char* file, int line, const char* format, ...) {
   fflush(stderr);
   v8::base::OS::Abort();
 }
+
+extern "C" void V8_RuntimeError(const char* file, int line,
+                                const char* message) {
+  fflush(stdout);
+  fflush(stderr);
+  v8::base::OS::PrintError("\n\n#\n# Runtime error in %s, line %d\n# ", file,
+                           line);
+  v8::base::OS::PrintError("\n# %s\n", message);
+  v8::base::DumpBacktrace();
+  fflush(stderr);
+}