FORTIFY_SOURCE: add fgets support.

Change-Id: I8c3410a90c71a3336c4ac8581618fa9330edf5e3
diff --git a/libc/Android.mk b/libc/Android.mk
index 06d36fe..6b1bba4 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -140,6 +140,7 @@
 	stdio/vsscanf.c \
 	stdio/wbuf.c \
 	stdio/wsetup.c \
+	stdio/__fgets_chk.c \
 	stdio/__snprintf_chk.c \
 	stdio/__sprintf_chk.c \
 	stdio/__vsnprintf_chk.c \