Fix "jst" GDB macro

tools/gdbinit

 # Copyright 2014 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.
 
 # Print HeapObjects.
 define job
 print ((v8::internal::HeapObject*)($arg0))->Print()
 end
 document job
 Print a v8 JavaScript object
 Usage: job tagged_ptr
 end
 
 # Print Code objects containing given PC.
 define jco
 job (v8::internal::Isolate::Current()->FindCodeObject((v8::internal::Address)$arg0))
 end
 document jco
 Print a v8 Code object from an internal code address
 Usage: jco pc
 end
 
 # Print JavaScript stack trace.
 define jst
-print v8::internal::Isolate::Current()->PrintStack(stdout)
+print v8::internal::Isolate::Current()->PrintStack((FILE*) stdout)
 end
 document jst
 Print the current JavaScript stack trace
 Usage: jst
 end
 
 set disassembly-flavor intel
 set disable-randomization off