Add inttypes.h for PRIu64.

This missing header is needed to use PRIu64 macros.

Bug: 27178350
TEST=`mma bootable/recovery` on the failing branch.

Change-Id: I165701e8019256426d3f6a4168db52c6a0197c4d
diff --git a/install.cpp b/install.cpp
index cde9cba..02c845c 100644
--- a/install.cpp
+++ b/install.cpp
@@ -17,6 +17,7 @@
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <inttypes.h>
 #include <limits.h>
 #include <string.h>
 #include <sys/stat.h>