fix compilation errors from server.c example

[mmsaki]

Server code example has some errors that I fixed on the PR

• updated addr_len to use type socklen_t
• fix the while condition to use == instead of =

[CLAassistant]

All committers have signed the CLA.

[drbruced12]

The change in line 330 is correct but the change to line 355/356 is not correct. We are not testing whether buf_len equals the return value of the recv call (bytes received); we are testing whether the recv call succeeded. If it returns zero bytes (nothing could be read) we exit the while loop.

If you remove the second change from the PR we will be able to merge it.

[mmsaki]

@drbruced12 I Fixed line 355/356