Add permitted_when_isolated_path to linker namespaces

The permitted_when_isolated_path is a way to white-list
directories not present in search-path. It is ignored for
not isolated namespaces.

Bug: http://b/25853516
Bug: http://b/22548808
Change-Id: Ib1538037268eea69323ea49968a34a4a1d1938a5

libdl/libdl.c

@@ -57,6 +57,7 @@ bool android_init_namespaces(const char* public_ns_sonames __unused,
 struct android_namespace_t* android_create_namespace(const char* name __unused,
                                                      const char* ld_library_path __unused,
                                                      const char* default_library_path __unused,
-                                                     bool isolated __unused) {
+                                                     bool isolated __unused,
+                                                     const char* permitted_when_isolated_path __unused) {
   return 0;
 }