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.

range.c

@@ -94,8 +94,7 @@ struct game_params {
 
 struct game_state {
     struct game_params params;
-    unsigned int has_cheated: 1;
-    unsigned int was_solved: 1;
+    bool has_cheated, was_solved;
     puzzle_size *grid;
 };
 
@@ -702,7 +701,7 @@ static char *new_game_desc(const game_params *params, random_state *rs,
     state.params = *params;
     state.grid = grid;
 
-    interactive = 0; /* I don't need it, I shouldn't use it*/
+    interactive = false; /* I don't need it, I shouldn't use it*/
 
     for (i = 0; i < n; ++i) shuffle_1toN[i] = i;
 
@@ -1221,7 +1220,7 @@ static char *game_text_format(const game_state *state)
 
 struct game_ui {
     puzzle_size r, c; /* cursor position */
-    unsigned int cursor_show: 1;
+    bool cursor_show;
 };
 
 static game_ui *new_ui(const game_state *state)
@@ -1248,15 +1247,13 @@ static void decode_ui(game_ui *ui, const char *encoding)
 
 typedef struct drawcell {
     puzzle_size value;
-    unsigned int error: 1;
-    unsigned int cursor: 1;
-    unsigned int flash: 1;
+    bool error, cursor, flash;
 } drawcell;
 
 struct game_drawstate {
     int tilesize;
     drawcell *grid;
-    unsigned int started: 1;
+    bool started;
 };
 
 #define TILESIZE (ds->tilesize)
@@ -1271,8 +1268,8 @@ static char *interpret_move(const game_state *state, game_ui *ui,
     enum {none, forwards, backwards, hint};
     int const w = state->params.w, h = state->params.h;
     int r = ui->r, c = ui->c, action = none, cell;
-    int shift = button & MOD_SHFT;
-    button &= ~shift;
+    bool shift = button & MOD_SHFT;
+    button &= ~MOD_SHFT;
 
     if (IS_CURSOR_SELECT(button) && !ui->cursor_show) return NULL;
 
@@ -1331,7 +1328,8 @@ static char *interpret_move(const game_state *state, game_ui *ui,
             for (i = 0; i < 4 && cursors[i] != button; ++i);
             assert (i < 4);
             if (shift) {
-                int pre_r = r, pre_c = c, do_pre, do_post;
+                int pre_r = r, pre_c = c;
+                bool do_pre, do_post;
                 cell = state->grid[idx(r, c, state->params.w)];
                 do_pre = (cell == EMPTY);
 
@@ -1407,7 +1405,7 @@ static char *interpret_move(const game_state *state, game_ui *ui,
     return NULL;
 }
 
-static int find_errors(const game_state *state, int *report)
+static bool find_errors(const game_state *state, bool *report)
 {
     int const w = state->params.w, h = state->params.h, n = w * h;
     int *dsf;
@@ -1543,7 +1541,7 @@ static game_state *execute_move(const game_state *state, const char *move)
         ret->grid[idx(r, c, ret->params.w)] = value;
     }
 
-    if (ret->was_solved == false)
+    if (!ret->was_solved)
         ret->was_solved = !find_errors(ret, NULL);
 
     return ret;
@@ -1626,7 +1624,8 @@ static float *game_colours(frontend *fe, int *ncolours)
     return ret;
 }
 
-static drawcell makecell(puzzle_size value, int error, int cursor, int flash)
+static drawcell makecell(puzzle_size value,
+                         bool error, bool cursor, bool flash)
 {
     drawcell ret;
     setmember(ret, value);
@@ -1660,7 +1659,7 @@ static void game_free_drawstate(drawing *dr, game_drawstate *ds)
 
 #define cmpmember(a, b, field) ((a) . field == (b) . field)
 
-static int cell_eq(drawcell a, drawcell b)
+static bool cell_eq(drawcell a, drawcell b)
 {
     return
         cmpmember(a, b, value) &&
@@ -1683,8 +1682,8 @@ static void game_redraw(drawing *dr, game_drawstate *ds,
 
     int r, c, i;
 
-    int *errors = snewn(n, int);
-    memset(errors, false, n * sizeof (int));
+    bool *errors = snewn(n, bool);
+    memset(errors, 0, n * sizeof (bool));
     find_errors(state, errors);
 
     assert (oldstate == NULL); /* only happens if animating moves */