Move linker config under /linkerconfig

Currently linker config locates under /dev, but this makes some problem
in case of using two system partitions with chroot. To match system
image and configuration, linker config better stays under /linkerconfig

Bug: 144966380
Test: m -j passed && tested from cuttelfish
Change-Id: Iaae5af65721eee8106311c1efb4760a9db13564a
diff --git a/init/mount_namespace.cpp b/init/mount_namespace.cpp
index 940fb6b..c33e0de 100644
--- a/init/mount_namespace.cpp
+++ b/init/mount_namespace.cpp
@@ -172,6 +172,11 @@
     // the bootstrap namespace get APEXes from the read-only partition.
     if (!(MakePrivate("/apex"))) return false;
 
+    // /linkerconfig is a private mountpoint to give a different linker configuration
+    // based on the mount namespace. Subdirectory will be bind-mounted based on current mount
+    // namespace
+    if (!(MakePrivate("/linkerconfig"))) return false;
+
     bootstrap_ns_fd.reset(OpenMountNamespace());
     bootstrap_ns_id = GetMountNamespaceId();