Cygwin: Fix compiling with w32api-headers v11.0.0

This solves redefinition of FILE_CS_FLAG_CASE_SENSITIVE_DIR in winnt.h
and fixes the following compiler errors

ntdll.h:523:3: error: expected identifier before numeric constant
  523 |   FILE_CS_FLAG_CASE_SENSITIVE_DIR                       = 0x01
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ntdll.h:522:1: note: to match this ‘{’
  522 | {
      | ^

winsup/cygwin/local_includes/ntdll.h

@@ -518,10 +518,12 @@ enum
   FILE_RENAME_IGNORE_READONLY_ATTRIBUTE			= 0x40
 };
 
+#if (__MINGW64_VERSION_MAJOR < 11)
 enum
 {
   FILE_CS_FLAG_CASE_SENSITIVE_DIR			= 0x01
 };
+#endif
 
 enum
 {