Fix printf formats

src/base/compiler-specific.h

 // 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.
 
 #ifndef V8_BASE_COMPILER_SPECIFIC_H_
 #define V8_BASE_COMPILER_SPECIFIC_H_
 
 #include "include/v8config.h"
 
 // Annotate a typedef or function indicating it's ok if it's not used.
 // Use like:
 //   typedef Foo Bar ALLOW_UNUSED_TYPE;
 #if V8_HAS_ATTRIBUTE_UNUSED
 #define ALLOW_UNUSED_TYPE __attribute__((unused))
 #else
 #define ALLOW_UNUSED_TYPE
 #endif
 
 
 // Annotate a function indicating the caller must examine the return value.
 // Use like:
 //   int foo() WARN_UNUSED_RESULT;
 #if V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
 #else
 #define WARN_UNUSED_RESULT /* NOT SUPPORTED */
 #endif
 
+// Tell the compiler a function is using a printf-style format string.
+// |format_param| is the one-based index of the format string parameter;
+// |dots_param| is the one-based index of the "..." parameter.
+// For v*printf functions (which take a va_list), pass 0 for dots_param.
+// (This is undocumented but matches what the system C headers do.)
+#if defined(__GNUC__)
+#define PRINTF_FORMAT(format_param, dots_param) \
+  __attribute__((format(printf, format_param, dots_param)))
+#else
+#define PRINTF_FORMAT(format_param, dots_param)
+#endif
 
 // The C++ standard requires that static const members have an out-of-class
 // definition (in a single compilation unit), but MSVC chokes on this (when
 // language extensions, which are required, are enabled). (You're only likely to
 // notice the need for a definition if you take the address of the member or,
 // more commonly, pass it to a function that takes it as a reference argument --
 // probably an STL function.) This macro makes MSVC do the right thing. See
 // http://msdn.microsoft.com/en-us/library/34h23df8(v=vs.100).aspx for more
 // information. Use like:
 //
 // In .h file:
 //   struct Foo {
 //     static const int kBar = 5;
 //   };
 //
 // In .cc file:
 //   STATIC_CONST_MEMBER_DEFINITION const int Foo::kBar;
 #if V8_HAS_DECLSPEC_SELECTANY
 #define STATIC_CONST_MEMBER_DEFINITION __declspec(selectany)
 #else
 #define STATIC_CONST_MEMBER_DEFINITION
 #endif
 
 #endif  // V8_BASE_COMPILER_SPECIFIC_H_