Android does not have _Exit. We detect this and use _exit instead.
clang-3.4 has an issue around undefined reference to
__atomic_fetch_add_4, so we stick to gcc-4.8 for now.
To distinguish the to-be-installed programs and non-installable
example source code, the former programs, spdycat, spdydyd and shrpx,
were moved to src directory. spdynative was removed from Makefile
because it does not appeal to any users much.
Tatsuhiro Tsujikawa