* Define lwIP's s32/u32 to int
s32/u32 were previously defined as long,
but long can be 64 bits in host mode,
so this commit reduces valgrind complaints and increase coherency.
* some lads like to use `unsigned long` for 32 bits IPv4 addresses
* fix lwIP's `sys_now()` return type
* fix C declarations
* merge upstream (lwip2) update on sys_now() definition
* matching lwIP api (2/2)
Co-authored-by: Max Prokhorov <prokhorov.max@outlook.com>
80c0570620