Add <stdio_ext.h> for elfutils.

Bug: 17139679
Change-Id: I1605ac382dbb6f23b2d874dbb9769f3cde4a6a99
diff --git a/libc/Android.mk b/libc/Android.mk
index 937f741..c268a87 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -62,6 +62,7 @@
     bionic/system_properties_compat.c \
     stdio/snprintf.c\
     stdio/sprintf.c \
+    stdio/stdio_ext.cpp \
 
 # Fortify implementations of libc functions.
 libc_common_src_files += \