Use C99 bool within source modules.

This is the main bulk of this boolification work, but although it's
making the largest actual change, it should also be the least
disruptive to anyone interacting with this code base downstream of me,
because it doesn't modify any interface between modules: all the
inter-module APIs were updated one by one in the previous commits.
This just cleans up the code within each individual source file to use
bool in place of int where I think that makes things clearer.

rect.c

@@ -44,7 +44,7 @@ enum {
 struct game_params {
     int w, h;
     float expandfactor;
-    int unique;
+    bool unique;
 };
 
 #define INDEX(state, x, y)    (((y) * (state)->w) + (x))
@@ -80,7 +80,7 @@ struct game_state {
     int *grid;			       /* contains the numbers */
     unsigned char *vedge;	       /* (w+1) x h */
     unsigned char *hedge;	       /* w x (h+1) */
-    int completed, cheated;
+    bool completed, cheated;
     unsigned char *correct;
 };
 
@@ -493,7 +493,7 @@ static int rect_solver(int w, int h, int nrects, struct numberdata *numbers,
      * Now run the actual deduction loop.
      */
     while (1) {
-        int done_something = false;
+        bool done_something = false;
 
 #ifdef SOLVER_DIAGNOSTICS
         printf("starting deduction loop\n");
@@ -606,7 +606,7 @@ static int rect_solver(int w, int h, int nrects, struct numberdata *numbers,
 
             for (j = 0; j < rectpositions[i].n; j++) {
                 int xx, yy, k;
-                int del = false;
+                bool del = false;
 
                 for (k = 0; k < nrects; k++)
                     workspace[k] = 0;
@@ -1814,7 +1814,8 @@ static unsigned char *get_correct(game_state *state)
 	    if (index(state,ret,x,y) == 0xFF) {
 		int rw, rh;
 		int xx, yy;
-		int num, area, valid;
+		int num, area;
+                bool valid;
 
 		/*
 		 * Find a rectangle starting at this point.
@@ -1908,7 +1909,8 @@ static game_state *new_game(midend *me, const game_params *params,
     state->grid = snewn(area, int);
     state->vedge = snewn(area, unsigned char);
     state->hedge = snewn(area, unsigned char);
-    state->completed = state->cheated = false;
+    state->completed = false;
+    state->cheated = false;
 
     i = 0;
     while (*desc) {
@@ -2161,12 +2163,12 @@ struct game_ui {
      * the pointer _returns_ to its starting point the action is
      * treated as a small drag rather than a click.
      */
-    int dragged;
+    bool dragged;
     /* This flag is set if we're doing an erase operation (i.e.
      * removing edges in the centre of the rectangle without altering
      * the outlines).
      */
-    int erasing;
+    bool erasing;
     /*
      * These are the co-ordinates of the top-left and bottom-right squares
      * in the drag box, respectively, or -1 otherwise.
@@ -2179,7 +2181,8 @@ struct game_ui {
      * These are the coordinates of a cursor, whether it's visible, and
      * whether it was used to start a drag.
      */
-    int cur_x, cur_y, cur_visible, cur_dragging;
+    int cur_x, cur_y;
+    bool cur_visible, cur_dragging;
 };
 
 static void reset_ui(game_ui *ui)
@@ -2200,7 +2203,9 @@ static game_ui *new_ui(const game_state *state)
     game_ui *ui = snew(game_ui);
     reset_ui(ui);
     ui->erasing = false;
-    ui->cur_x = ui->cur_y = ui->cur_visible = ui->cur_dragging = 0;
+    ui->cur_x = ui->cur_y = 0;
+    ui->cur_visible = false;
+    ui->cur_dragging = false;
     return ui;
 }
 
@@ -2305,13 +2310,13 @@ static void coord_round(float x, float y, int *xr, int *yr)
 /*
  * Returns true if it has made any change to the grid.
  */
-static int grid_draw_rect(const game_state *state,
+static bool grid_draw_rect(const game_state *state,
 			  unsigned char *hedge, unsigned char *vedge,
-			  int c, int really, int outline,
+			  int c, bool really, bool outline,
 			  int x1, int y1, int x2, int y2)
 {
     int x, y;
-    int changed = false;
+    bool changed = false;
 
     /*
      * Draw horizontal edges of rectangles.
@@ -2350,9 +2355,9 @@ static int grid_draw_rect(const game_state *state,
     return changed;
 }
 
-static int ui_draw_rect(const game_state *state, const game_ui *ui,
+static bool ui_draw_rect(const game_state *state, const game_ui *ui,
 			unsigned char *hedge, unsigned char *vedge, int c,
-			int really, int outline)
+			bool really, bool outline)
 {
     return grid_draw_rect(state, hedge, vedge, c, really, outline,
 			  ui->x1, ui->y1, ui->x2, ui->y2);
@@ -2364,7 +2369,7 @@ static void game_changed_state(game_ui *ui, const game_state *oldstate,
 }
 
 struct game_drawstate {
-    int started;
+    bool started;
     int w, h, tilesize;
     unsigned long *visible;
 };
@@ -2374,7 +2379,7 @@ static char *interpret_move(const game_state *from, game_ui *ui,
                             int x, int y, int button)
 {
     int xc, yc;
-    int startdrag = false, enddrag = false, active = false, erasing = false;
+    bool startdrag = false, enddrag = false, active = false, erasing = false;
     char buf[80], *ret;
 
     button &= ~MOD_MASK;
@@ -2398,7 +2403,7 @@ static char *interpret_move(const game_state *from, game_ui *ui,
         enddrag = true;
         erasing = (button == RIGHT_RELEASE);
     } else if (IS_CURSOR_MOVE(button)) {
-        move_cursor(button, &ui->cur_x, &ui->cur_y, from->w, from->h, 0);
+        move_cursor(button, &ui->cur_x, &ui->cur_y, from->w, from->h, false);
         ui->cur_visible = true;
         active = true;
         if (!ui->cur_dragging) return UI_UPDATE;
@@ -2586,7 +2591,8 @@ static game_state *execute_move(const game_state *from, const char *move)
      * if the game has been completed.
      */
     if (!ret->completed) {
-	int x, y, ok;
+	int x, y;
+        bool ok;
 
 	ok = true;
 	for (x = 0; x < ret->w; x++)