Make common BitVector operations inline-able.

Change-Id: Ie25de4fae56c6712539f04172c42e3eff57df7ca
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 0fb1575..41a91ed 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -18,6 +18,7 @@
 
 #include <zlib.h>
 
+#include "base/allocator.h"
 #include "base/bit_vector.h"
 #include "base/stl_util.h"
 #include "base/unix_file/fd_file.h"