diff --git a/ldb/os-common.c b/ldb/os-common.c
index b3689e0bb615e916064afd97c4ae0c9035090c57..9829c8c05a071190981c26320ab38343f60fb239 100644
--- a/ldb/os-common.c
+++ b/ldb/os-common.c
@@ -42,6 +42,13 @@ os_vm_size_t len;
     return os_validate((os_vm_address_t)NULL,len);
 }
 
+os_vm_address_t os_allocate_at(addr,len)
+os_vm_address_t addr;
+os_vm_size_t len;
+{
+    return os_validate(&addr, len);
+}
+
 void os_deallocate(addr,len)
 os_vm_address_t addr;
 os_vm_size_t len;