vold should #include <sys/sysmacros.h>

Bug: https://github.com/android-ndk/ndk/issues/398
Test: builds
Change-Id: I7a1ca1701099886fb493cc5288d6ee867d5f520a
diff --git a/EmulatedVolume.cpp b/EmulatedVolume.cpp
index 581c322..44ad22a 100644
--- a/EmulatedVolume.cpp
+++ b/EmulatedVolume.cpp
@@ -27,6 +27,7 @@
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/sysmacros.h>
 #include <sys/wait.h>
 
 using android::base::StringPrintf;