only free stream if we opened it

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
change test argument signature to void

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
t/01-sanity: remove useless stdio.h include

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
enable -Wextra for all tests

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
add tap.c as dependency for tests

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
t/Makefile: avoid modifying PATH to run tests

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
t/Makefile: add note about tap.c submodule

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>