aom_thread: Fix leaking min/max macros

This breaks building noise_model_test and others on MSVC.

Followup to I692b03fa3e70b7a53962d3fd209498f70f712fed.

Change-Id: I87354334d16a7503ddc5c19ea1d68fa829a67de4
(cherry picked from commit 3dbb8cabfbe1d7aabc212af23e65dd184d02493e)

aom_util/aom_thread.h

diff --git a/aom_util/aom_thread.h b/aom_util/aom_thread.h
index 8d04312..6750f1a 100644
--- a/aom_util/aom_thread.h
+++ b/aom_util/aom_thread.h
@@ -28,6 +28,10 @@
 #if CONFIG_MULTITHREAD
 
 #if defined(_WIN32) && !HAVE_PTHREAD_H
+// Prevent leaking max/min macros.
+#undef NOMINMAX
+#define NOMINMAX
+#define WIN32_LEAN_AND_MEAN
 #include <errno.h>    // NOLINT
 #include <process.h>  // NOLINT
 #include <windows.h>  // NOLINT