ANSI C and POSIX
-------------------------
The code should compile without any warning in a system providing an ANSI C
compiler and a Single Unix Specification rev 5 library. I tried only with glibc.

If you find any inconsistency between the code and this statement, please let
know the auther.

Compilers
-------------------------
(Lluís) I could compile easily with gcc.
I could also compile with tcc 0.9.22 if I change the features to
-D_XOPEN_SOURCE -D_XOPEN_SOURCE_EXTENDED -D__STRICT_ANSI__
But the linking didn't work with tcc.

HP-UX 10.2 in PA-RISC
-------------------------
(Lluís) I could compile changing the #include for sys/select.h in server.c to
sys/time.h. I also had to use gcc instead of the system's cc.