try to pass compiling with VC12

* win32/win32.c (FILE_ID_128): it's not defined in SDK with VC10, but seems to
  be defined in SDK with VC12.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61007 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

win32/win32.c

@@ -7895,12 +7895,14 @@ rb_w32_pow(double x, double y)
 }
 #endif
 
-#if !defined(_WIN32_WINNT_WIN8) || _WIN32_WINNT < 0x602
-#define FileIdInfo 0x12
-
+#ifndef FILE_INVALID_FILE_ID
 typedef struct {
     BYTE  Identifier[16];
 } FILE_ID_128;
+#endif
+
+#if !defined(_WIN32_WINNT_WIN8) || _WIN32_WINNT < 0x602
+#define FileIdInfo 0x12
 
 typedef struct {
     unsigned LONG_LONG VolumeSerialNumber;