Use C99 printf statements in mingw

Otherwise, format specifiers such as %llu will not work on XP or
earlier.
This bug was introduced with 51ed9ec9.
http://sourceforge.net/apps/trac/mingw-w64/wiki/gnu%20printf

configure.ac

@@ -221,7 +221,7 @@ case $host in
        AC_MSG_ERROR("windres not found")
      fi
 
-     CPPFLAGS="$CPPFLAGS -D_MT -DWIN32 -D_WINDOWS -DBOOST_THREAD_USE_LIB"
+     CPPFLAGS="$CPPFLAGS -D_MT -DWIN32 -D_WINDOWS -DBOOST_THREAD_USE_LIB -D__USE_MINGW_ANSI_STDIO"
      LEVELDB_TARGET_FLAGS="TARGET_OS=OS_WINDOWS_CROSSCOMPILE"
      CXXFLAGS="$CXXFLAGS -w"
      ;;

src/util.cpp

@@ -336,11 +336,7 @@ string vstrprintf(const char *format, va_list ap)
     {
         va_list arg_ptr;
         va_copy(arg_ptr, ap);
-#ifdef WIN32
-        ret = _vsnprintf(p, limit, format, arg_ptr);
-#else
         ret = vsnprintf(p, limit, format, arg_ptr);
-#endif
         va_end(arg_ptr);
         if (ret >= 0 && ret < limit)
             break;

src/util.h

@@ -44,26 +44,13 @@ static const int64_t CENT = 1000000;
 #define UEND(a)             ((unsigned char*)&((&(a))[1]))
 #define ARRAYLEN(array)     (sizeof(array)/sizeof((array)[0]))
 
-/* Format characters for (s)size_t and ptrdiff_t */
-#if defined(_MSC_VER) || defined(__MSVCRT__)
-  /* (s)size_t and ptrdiff_t have the same size specifier in MSVC:
-     http://msdn.microsoft.com/en-us/library/tcxf1dw6%28v=vs.100%29.aspx
-   */
-  #define PRIszx    "Ix"
-  #define PRIszu    "Iu"
-  #define PRIszd    "Id"
-  #define PRIpdx    "Ix"
-  #define PRIpdu    "Iu"
-  #define PRIpdd    "Id"
-#else /* C99 standard */
+/* Format characters for (s)size_t and ptrdiff_t (C99 standard) */
 #define PRIszx    "zx"
 #define PRIszu    "zu"
 #define PRIszd    "zd"
 #define PRIpdx    "tx"
 #define PRIpdu    "tu"
 #define PRIpdd    "td"
-#endif
-
 
 // This is needed because the foreach macro can't get over the comma in pair<t1, t2>
 #define PAIRTYPE(t1, t2)    std::pair<t1, t2>
@@ -117,7 +104,7 @@ inline void MilliSleep(int64_t n)
  * Parameters count from 1.
  */
 #ifdef __GNUC__
-#define ATTR_WARN_PRINTF(X,Y) __attribute__((format(printf,X,Y)))
+#define ATTR_WARN_PRINTF(X,Y) __attribute__((format(gnu_printf,X,Y)))
 #else
 #define ATTR_WARN_PRINTF(X,Y)
 #endif