Indicate default MIDI port in man page

configure.ac

@@ -35,6 +35,7 @@ AC_ARG_WITH([oss],
                     midi_default_port="/dev/midi00"])])
 AC_DEFINE_UNQUOTED([DEFAULT_MIDI_PORT], ["$midi_default_port"],
                    [Default MIDI port to use.])
+AC_SUBST([DEFAULT_MIDI_PORT], [$midi_default_port])
 
 dnl Check for selected backend
 AS_CASE(["x$midi_backend"],
@@ -50,7 +51,8 @@ AS_CASE(["x$midi_backend"],
         [AC_MSG_ERROR([No MIDI backend selected.])])
 
 dnl Output files
-AC_CONFIG_FILES([Makefile lib/Makefile src/Makefile man/Makefile])
+AC_CONFIG_FILES([Makefile lib/Makefile src/Makefile
+                 man/Makefile man/asysex.1])
 AC_OUTPUT
 
 dnl Summary

man/asysex.1.in

@@ -31,6 +31,7 @@ Display the version message.
 .TP
 .BR -p ", " --port " " \fIport\fR
 Connect to the specified MIDI \fIport\fR.
+If not specified, default is \(lq@DEFAULT_MIDI_PORT@\(rq.
 .TP
 .BR -I ", " --inquiry
 Identify the connected MIDI device and exit.