[lwip-users] Compile warnings

[Bob Ammerman]

When compiling lwIP with the Microsoft Visual C++ I am getting a lot of
warnings. I'd like to clean up the code to correct them. I also plan on
helping to enhance and improve the lwIP package. (I have previously built a
compliant implementation of IP, ICMP, ARP and UDP from scratch). What do I
need to do to be able to generate fixes?

Bob Ammerman
RAm Systems

==== Example:

return ~(acc & 0xffff);

Results in:

'return' : conversion from 'unsigned long ' to 'unsigned short ', possible
loss of data

To correct it:

 return (u16_t) ~acc;


There are also signed/unsigned mismatches, and argument size mismatch errors
that should be cleaned up.