bin: separate process_file() for aut and ltl

* bin/common_finput.cc, bin/common_finput.hh,
bin/common_hoaread.hh (process_file): Split into...
(process_ltl_file, process_aut_filt): ... these, as we will need both
in ltlsynt.

bin/common_finput.cc

@@ -303,7 +303,13 @@ job_processor::process_stream(std::istream& is,
 }
 
 int
-job_processor::process_file(const char* filename)
+job_processor::process_aut_file(const char*)
+{
+  throw std::runtime_error("process_aut_file not defined for this tool");
+}
+
+int
+job_processor::process_ltl_file(const char* filename)
 {
   col_to_read = 0;
 
@@ -366,8 +372,10 @@ job_processor::run()
           error |= process_string(j.str);
           break;
         case job_type::LTL_FILENAME:
+          error |= process_ltl_file(j.str);
+          break;
         case job_type::AUT_FILENAME:
-          error |= process_file(j.str);
+          error |= process_aut_file(j.str);
           break;
         default:
           throw std::runtime_error("unexpected job type");

bin/common_finput.hh

@@ -72,7 +72,10 @@ public:
   process_stream(std::istream& is, const char* filename);
 
   virtual int
-  process_file(const char* filename);
+  process_ltl_file(const char* filename);
+
+  virtual int
+  process_aut_file(const char* filename);
 
   virtual int
   run();

bin/common_hoaread.hh

@@ -1,6 +1,6 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2015, 2017, 2018 Laboratoire de Recherche et Développement de
+// Copyright (C) 2015, 2017, 2018, 2022 Laboratoire de Recherche et
-// l'Epita (LRDE).
+// Développement de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
 //
@@ -80,8 +80,10 @@ public:
   }
 
   int
-  process_file(const char* filename) override
+  process_aut_file(const char* filename) override
   {
+    col_to_read = 0;
+
     // If we have a filename like "foo/NN" such
     // that:
     // ① foo/NN is not a file,