[Sanitizer] Use kStderrFd constant instead of hardcoded 2

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@167291 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/sanitizer_common/sanitizer_win.cc b/lib/sanitizer_common/sanitizer_win.cc
index dbacc5a..8919341 100644
--- a/lib/sanitizer_common/sanitizer_win.cc
+++ b/lib/sanitizer_common/sanitizer_win.cc
@@ -163,7 +163,7 @@
 }
 
 uptr internal_write(fd_t fd, const void *buf, uptr count) {
-  if (fd != 2)
+  if (fd != kStderrFd)
     UNIMPLEMENTED();
   HANDLE err = GetStdHandle(STD_ERROR_HANDLE);
   if (err == 0)