build: add debug configure flag

Signed-off-by: Thynson <lanxingcan@gmail.com>
export spin_init and spin_uninit, user need to manually call them

Signed-off-by: Thynson <lanxingcan@gmail.com>
Add spin_debug

Signed-off-by: Thynson <lanxingcan@gmail.com>
rename spin_poller to spin_global

Signed-off-by: Thynson <lanxingcan@gmail.com>
move misc function to spin.h

Signed-off-by: Thynson <lanxingcan@gmail.com>
Add testcases

Signed-off-by: Thynson <lanxingcan@gmail.com>
add test-socket-02.c

Signed-off-by: Thynson <lanxingcan@gmail.com>
update test-socket-02.c as a echo server

Signed-off-by: Thynson <lanxingcan@gmail.com>
test link list

Signed-off-by: Thynson <lanxingcan@gmail.com>
test: auto close socket

Signed-off-by: Thynson <lanxingcan@gmail.com>
Add spin_init()/spin_uninit() in test code

Signed-off-by: Thynson <lanxingcan@gmail.com>