Add missing includes.

Change-Id: Ibf549266a19a67eb9158d341a69dddfb654be669
diff --git a/linker/linker_allocator.cpp b/linker/linker_allocator.cpp
index 92220e8..ac11b97 100644
--- a/linker/linker_allocator.cpp
+++ b/linker/linker_allocator.cpp
@@ -13,8 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 #include "linker_allocator.h"
 #include <inttypes.h>
+#include <string.h>
 #include <sys/mman.h>
 #include <unistd.h>