Make RUNTIME_ASSERT have more useful output in debug mode

src/base/logging.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/logging.h"
 
 #if V8_LIBC_GLIBC || V8_OS_BSD
 #include <cxxabi.h>
 #include <dlfcn.h>
 #include <execinfo.h>
@@ skipping 97 matching lines @@
                            line);
   va_list arguments;
   va_start(arguments, format);
   v8::base::OS::VPrintError(format, arguments);
   va_end(arguments);
   v8::base::OS::PrintError("\n#\n");
   v8::base::DumpBacktrace();
   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);
+}