Ensure there is some space on JS stack available for bootstrapping.

src/isolate.h

 // Copyright 2012 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.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <queue>
 #include "include/v8-debug.h"
 #include "src/allocation.h"
@@ skipping 1463 matching lines @@
  public:
   explicit StackLimitCheck(Isolate* isolate) : isolate_(isolate) { }
 
   // Use this to check for stack-overflows in C++ code.
   inline bool HasOverflowed() const {
     StackGuard* stack_guard = isolate_->stack_guard();
     return GetCurrentStackPosition() < stack_guard->real_climit();
   }
 
   // Use this to check for stack-overflow when entering runtime from JS code.
-  bool JsHasOverflowed() const;
+  bool JsHasOverflowed(uintptr_t gap = 0) const;
 
  private:
   Isolate* isolate_;
 };
 
 
 // Support for temporarily postponing interrupts. When the outermost
 // postpone scope is left the interrupts will be re-enabled and any
 // interrupts that occurred while in the scope will be taken into
 // account.
@@ skipping 89 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_