diff --git a/llvm/lib/Support/Unix/Threading.inc b/llvm/lib/Support/Unix/Threading.inc
index a354984cabb1e..c7b4c7af3b9f3 100644
--- a/llvm/lib/Support/Unix/Threading.inc
+++ b/llvm/lib/Support/Unix/Threading.inc
@@ -33,6 +33,13 @@
 #include <pthread_np.h> // For pthread_getthreadid_np() / pthread_set_name_np()
 #endif
 
+// Must be included after Threading.inc to provide definition for llvm::thread
+// because FreeBSD's condvar.h (included by user.h) misuses the "thread"
+// keyword.
+#ifndef __FreeBSD__
+#include "llvm/Support/thread.h"
+#endif
+
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
 #include <errno.h>
 #include <sys/cpuset.h>
diff --git a/llvm/lib/Support/Windows/Threading.inc b/llvm/lib/Support/Windows/Threading.inc
index 4baf8b8cb82ae..d862dbd7f71c9 100644
--- a/llvm/lib/Support/Windows/Threading.inc
+++ b/llvm/lib/Support/Windows/Threading.inc
@@ -12,6 +12,7 @@
 
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/thread.h"
 
 #include "llvm/Support/Windows/WindowsSupport.h"
 #include <process.h>