Include sys/byteorder.h for htons and friends.

These are usually in netinet/in.h but on HP-UX they are not defined if
_XOPEN_SOURCE_EXTENDED is set.  Only needed for netcat in the regression
tests.

configure.ac

@@ -413,6 +413,7 @@ AC_CHECK_HEADERS([ \
 	string.h \
 	strings.h \
 	sys/bitypes.h \
+	sys/byteorder.h \
 	sys/bsdtty.h \
 	sys/cdefs.h \
 	sys/dir.h \

regress/netcat.c

@@ -64,6 +64,9 @@
 #ifdef HAVE_ERR_H
 # include <err.h>
 #endif
+#ifndef HAVE_SYS_BYTEORDER_H
+# include <sys/byteorder.h>
+#endif
 
 /* Telnet options from arpa/telnet.h */
 #define IAC	255