The error message was:

warning: macro expansion producing 'defined' has undefined
behavior [-Wexpansion-to-defined]

http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20160118/147239.html

Previously we wrongly handles stream per connection when h2 backend
failed or closed.  If upstream is h2 or spdy, streams which are not
associated to the failed h2 backend are also handled, which is
unnecessary.

nghttp2_option_set_max_deflate_dynamic_table_size function sets the
maximum dynamic table size for header block deflater.  The default
value is 4KiB.

Move DATA frame handling code to switch-case of frame type.

tls_sni returns TLS SNI value which client sent in this TLS
connection.