Make sure we use the correct style of filepath separator on Windows

('libs/ardour/file_source.cc' still to be investigated)

libs/ardour/session_state.cc

@@ -916,7 +916,7 @@ Session::state (bool full_state)
 				p += (*i).path;
 
 				if (next != session_dirs.end()) {
-					p += ':';
+					p += G_DIR_SEPARATOR;
 				} else {
 					break;
 				}
@@ -2680,7 +2680,7 @@ Session::cleanup_sources (CleanupReport& rep)
 		audio_path += sdir.sound_path();
 
 		if (nexti != session_dirs.end()) {
-			audio_path += ':';
+			audio_path += G_DIR_SEPARATOR;
 		}
 
 		i = nexti;
@@ -2698,7 +2698,7 @@ Session::cleanup_sources (CleanupReport& rep)
 		midi_path += sdir.midi_path();
 
 		if (nexti != session_dirs.end()) {
-			midi_path += ':';
+			midi_path += G_DIR_SEPARATOR;
 		}
 
 		i = nexti;

libs/pbd/pathexpand.cc

@@ -174,7 +174,7 @@ PBD::search_path_expand (string path)
 	vector<string> s;
 	vector<string> n;
 
-	split (path, s, ':');
+	split (path, s, G_SEARCHPATH_SEPARATOR);
 
 	for (vector<string>::iterator i = s.begin(); i != s.end(); ++i) {
 		string exp = path_expand (*i);
@@ -187,7 +187,7 @@ PBD::search_path_expand (string path)
 
 	for (vector<string>::iterator i = n.begin(); i != n.end(); ++i) {
 		if (!r.empty()) {
-			r += ':';
+			r += G_SEARCHPATH_SEPARATOR;
 		}
 		r += *i;
 	}

libs/pbd/pathscanner.cc

@@ -170,7 +170,7 @@ PathScanner::run_scan_internal (vector<string *> *result,
 		}
 		closedir (dir);
 		
-	} while ((limit < 0 || (nfound < limit)) && (thisdir = strtok (0, ":")));
+	} while ((limit < 0 || (nfound < limit)) && (thisdir = strtok (0, G_SEARCHPATH_SEPARATOR_S)));
 
 	free (pathcopy);
 	return result;

libs/pbd/search_path.cc

@@ -133,7 +133,7 @@ export_search_path (const string& base_dir, const char* varname, const char* dir
 
 	if (cstr) {
 		path = cstr;
-		path += ':';
+		path += G_DIR_SEPARATOR;
 	} else {
 		path = "";
 	}