Add missing BEGIN_DECLS/END_DECLS for FORTIFY_SOURCE stdio prototypes.

Change-Id: I35ceb09fedf873c5e98e1e26efce5e4f00a17e74
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 3f453fe..20a9829 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -478,6 +478,8 @@
 
 #if defined(__BIONIC_FORTIFY_INLINE)
 
+__BEGIN_DECLS
+
 __BIONIC_FORTIFY_INLINE
 __attribute__((__format__ (printf, 3, 0)))
 __attribute__((__nonnull__ (3)))
@@ -553,6 +555,8 @@
     return __fgets_chk(dest, size, stream, bos);
 }
 
+__END_DECLS
+
 #endif /* defined(__BIONIC_FORTIFY_INLINE) */
 
 #endif /* _STDIO_H_ */