doc: add a spot(7) man page

Suggested by Akim Demaille.  Fixes #171.

* bin/man/spot.x, bin/spot.cc: New files.
* bin/man/Makefile.am, bin/Makefile.am: Add them.
* doc/org/tools.org, NEWS: Mention the new page.

bin/spot.cc

@@ -0,0 +1,78 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2013, 2014, 2015, 2016 Laboratoire de Recherche et
+// Développement de l'Epita (LRDE).
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "common_sys.hh"
+#include <string>
+#include <iostream>
+#include <cstdlib>
+#include <argp.h>
+#include "common_setup.hh"
+
+const char argp_program_doc[] ="Command-line tools installed by Spot.";
+
+#define DOC(NAME, TXT) NAME, 0, nullptr, OPTION_DOC | OPTION_NO_USAGE, TXT, 0
+
+static const argp_option options[] =
+  {
+    { nullptr, 0, nullptr, 0, "Tools that output LTL/PSL formulas:", 0 },
+    { DOC("randltl", "Generate random LTL or PSL formulas.") },
+    { DOC("genltl", "Generate LTL formulas from scalable patterns.") },
+    { DOC("ltlfilt", "Filter, convert, and transform LTL or PSL formulas.") },
+    { DOC("ltlgrind", "Mutate LTL or PSL formulas to generate similar but "
+          "simpler ones.  Use this when looking for shorter formula to "
+          "reproduce a bug.") },
+    { nullptr, 0, nullptr, 0, "Tools that output automata:", 0 },
+    { DOC("randaut", "Generate random ω-automata.") },
+    { DOC("ltl2tgba", "Convert LTL or PSL into variants of Transition-based "
+          "Generalized Büchi Automata.") },
+    { DOC("ltl2tgta", "Convert LTL or PSL into variants of Transition-based "
+          "Generalized Testing Automata.") },
+    { DOC("autfilt", "Filter, convert, and transform ω-automata.") },
+    { DOC("dstar2tgba", "Convert ω-automata into variants of "
+          "Transition-based Büchi automata.") },
+    { nullptr, 0, nullptr, 0, "Tools that run other tools:", 0 },
+    { DOC("ltlcross", "Cross-compare translators of LTL or PSL formulas "
+          "into ω-automata, watch for bugs, and generate statistics.") },
+    { DOC("ltldo", "Wrap any tool that inputs LTL or PSL formulas and possibly "
+          "outputs ω-automata; provides Spot's I/O interface.") },
+    { nullptr, 0, nullptr, 0, nullptr, 0 }
+  };
+
+const struct argp_child children[] =
+  {
+    { &misc_argp_hidden, 0, nullptr, -1 },
+    { nullptr, 0, nullptr, 0 }
+  };
+
+int
+main(int argc, char** argv)
+{
+  setup(argv);
+
+  const argp ap = { options, nullptr, nullptr, argp_program_doc, children,
+                    nullptr, nullptr };
+
+  if (int err = argp_parse(&ap, argc, argv, ARGP_NO_HELP, nullptr, nullptr))
+    exit(err);
+
+  std::cerr << "This binary serves no purpose other than generating"
+            << " the spot.7 manpage.\n";
+
+  return 1;
+}