Adding sub-tool support to Fill tool

Currently only one sub-tool (Solid) shown, as no code for new
tools has been added yet.  (Plans for linear & radial gradients.)

src/fill_tools.h

@@ -0,0 +1,67 @@
+/*
+  fill_tools.h
+
+  Fill tool -- tool variations (for selector)
+  Tux Paint - A simple drawing program for children.
+
+  Copyright (c) 2002-2019 by Bill Kendrick and others; see AUTHORS.txt
+  bill@newbreedsoftware.com
+  http://www.tuxpaint.org/
+
+  Flood fill code based on Wikipedia example:
+  http://www.wikipedia.org/wiki/Flood_fill/C_example
+  by Damian Yerrick - http://www.wikipedia.org/wiki/Damian_Yerrick
+
+  This program 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 2 of the License, or
+  (at your option) any later version.
+
+  This program 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, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  (See COPYING.txt)
+
+  Last updated: February 20, 2021
+  $Id$
+*/
+
+#ifndef FILL_TOOLS_H
+#define FILL_TOOLS_H
+
+#ifndef gettext_noop
+#define gettext_noop(String) String
+#endif
+
+enum {
+  FILL_FLOOD,
+  // FILL_GRADIENT_LINEAR,
+  // FILL_GRADIENT_RADIAL,
+  NUM_FILLS
+};
+
+const char *const fill_names[NUM_FILLS] = {
+  gettext_noop("Solid Color") /* ,
+  gettext_noop("Gradient (Line)"),
+  gettext_noop("Gradient (Radial)") */
+};
+
+const char *const fill_tips[NUM_FILLS] = {
+  gettext_noop("Click to fill an area with a solid color.") /* ,
+  gettext_noop("Click and drag to fill an area with a gradient from the chosen color to transparent."),
+  gettext_noop("Click to fill an area with a radial gradient from the chosen color to transparent.") */
+};
+
+const char *const fill_img_fnames[NUM_FILLS] = {
+  DATA_PREFIX "images/fills/solid.png" /* ,
+  DATA_PREFIX "images/fills/gradient_linear.png",
+  DATA_PREFIX "images/fills/gradient_radial.png" */
+};
+
+#endif
+