tests/utils.h should #include <sys/sysmacros.h>

Bug: https://github.com/android-ndk/ndk/issues/398
Test: builds
Change-Id: Ie81b49787d468e409db4024763f29946d3e4250f
diff --git a/tests/utils.h b/tests/utils.h
index 2e9b994..e3e0b0d 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -19,6 +19,7 @@
 
 #include <inttypes.h>
 #include <sys/mman.h>
+#include <sys/sysmacros.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>