diff --git a/extern/libmv/libmv/tracking/brute_region_tracker.cc b/extern/libmv/libmv/tracking/brute_region_tracker.cc
index 5b840e10857..c33432b7fd7 100644
--- a/extern/libmv/libmv/tracking/brute_region_tracker.cc
+++ b/extern/libmv/libmv/tracking/brute_region_tracker.cc
@@ -28,6 +28,10 @@
 // Needed for memalign on Linux and _aligned_alloc on Windows.
 #ifdef FREE_WINDOWS
 /* make sure _aligned_malloc is included */
+#ifdef __MSVCRT_VERSION__
+#undef __MSVCRT_VERSION__
+#endif
+
 #define __MSVCRT_VERSION__ 0x0700
 #endif