Add missing <malloc.h> and <string.h> includes.

Change-Id: Ia41756e607663d056e7d2fdd7ecbec7e5841a913
diff --git a/libsync/sync.c b/libsync/sync.c
index 4892866..d73bb11 100644
--- a/libsync/sync.c
+++ b/libsync/sync.c
@@ -17,6 +17,7 @@
  */
 
 #include <fcntl.h>
+#include <malloc.h>
 #include <stdint.h>
 #include <string.h>