libglnx: Update to latest

This pulls in a new compilation flag for wrpseudo compatibility.  Also
note we need to add some includes since glnx-libcontainer went away,
and with it some includes for `sys/mount.h` etc.

Closes: #522
Approved by: cgwalters

src/libostree/ostree-sysroot.c

@@ -21,6 +21,8 @@
 #include "config.h"
 
 #include "otutil.h"
+#include <sys/mount.h>
+#include <sys/wait.h>
 
 #include "ostree-core-private.h"
 #include "ostree-sysroot-private.h"