removed useless macro, implicit casts are a thing in C
remove typedef

using a typedef for 3 occurances of a type does *not* make things simpler.
No typedefs are worth the context switches, and you better have a good reason
for one used just _3_ times.

Actually default to port "4242" like in the README.md.
updated open_listenfd to 2014

getaddrinfo is like ... 15 years old
replace ~20 function calls with a single call and assignment.

Unless HTTP requires individual packets for single lines of HTML, I think this
is a no-brainer change. Someone please correct me if I'm wrong.
again sprintf is so old and unsafe.

Why do people still even consider that a thing to do?
This is a web framework for the *internet*. That's the one place where can
expect malicious input.
any platforms not supporting C99 are not worth considering
disclaimer