Include arpa/inet.h, since that's where htons() and friends are
supposed to be defined according to XPG4.2.
Found by Evan <n2xjk@ulster.net> for the MVS platform.
diff --git a/e_os.h b/e_os.h
index 0c0784f..4f9c983 100644
--- a/e_os.h
+++ b/e_os.h
@@ -355,12 +355,14 @@
# if defined(VMS) && !defined(__DECC)
# include <socket.h>
# include <in.h>
+# include <inet.h>
# else
# include <sys/socket.h>
# ifdef FILIO_H
# include <sys/filio.h> /* Added for FIONBIO under unixware */
# endif
# include <netinet/in.h>
+# include <arpa/inet.h>
# endif
# if defined(NeXT) || defined(_NEXT_SOURCE)