diff --git a/lib/krb5/krb5_locl.h b/lib/krb5/krb5_locl.h
index d0ee35d26..9167e47f0 100644
--- a/lib/krb5/krb5_locl.h
+++ b/lib/krb5/krb5_locl.h
@@ -123,6 +123,8 @@ struct sockaddr_dl;
 #include <asn1_err.h>
 #include <krb5-private.h>
 
+#include "heim_threads.h"
+
 #define ALLOC(X, N) (X) = calloc((N), sizeof(*(X)))
 #define ALLOC_SEQ(X, N) do { (X)->len = (N); ALLOC((X)->val, (N)); } while(0)