Add missing includes.

Test: mma
Bug: None
Change-Id: I0221b213e08d07cc5ac0b704a86e98ae8c0f456f
diff --git a/libc/bionic/iconv.cpp b/libc/bionic/iconv.cpp
index b0372a1..015d70f 100644
--- a/libc/bionic/iconv.cpp
+++ b/libc/bionic/iconv.cpp
@@ -32,6 +32,7 @@
 #include <endian.h>
 #include <errno.h>
 #include <stdlib.h>
+#include <string.h>
 #include <uchar.h>
 
 #include "private/bionic_mbstate.h"