Change int -> bool where applicable throughout varobj

This patch changes all the "int" I could find in varobj.{c,h} that are
really boolean values to use bool.  I followed the ramifications
(parameters and return values of exported functions), so the changes
spilled a bit on other, related files (ada-varobj.c and c-varobj.c).

gdb/ChangeLog:

	* ada-varobj.c (ada_value_is_changeable_p): Change int to bool where applicable.
	(ada_value_has_mutated): Likewise.
	* c-varobj.c (varobj_is_anonymous_child): Likewise.
	(c_is_path_expr_parent): Likewise.
	* mi/mi-cmd-var.c (varobj_update_one): Likewise.
	(mi_cmd_var_set_frozen): Likewise.
	(mi_cmd_var_update_iter): Likewise.
	(mi_cmd_var_update): Likewise.
	* varobj.c (pretty_printing): Likewise.
	(varobj_enable_pretty_printing): Likewise.
	(struct varobj_root) <floating, is_valid>: Likewise.
	(struct varobj_dynamic) <children_requested>: Likewise.
	(delete_variable): Likewise.
	(delete_variable_1): Likewise.
	(install_variable): Likewise.
	(update_type_if_necessary): Likewise.
	(install_new_value): Likewise.
	(value_of_root): Likewise.
	(is_root_p): Likewise.
	(varobj_create): Likewise.
	(varobj_delete): Likewise.
	(varobj_has_more): Likewise.
	(varobj_set_frozen): Likewise.
	(varobj_get_frozen): Likewise.
	(install_dynamic_child): Likewise.
	(dynamic_varobj_has_child_method): Likewise.
	(update_dynamic_varobj_children): Likewise.
	(varobj_get_num_children): Likewise.
	(varobj_list_children): Likewise.
	(is_path_expr_parent): Likewise.
	(varobj_default_is_path_expr_parent): Likewise.
	(varobj_is_dynamic_p): Likewise.
	(varobj_set_value): Likewise.
	(varobj_value_has_mutated): Likewise.
	(varobj_update): Likewise.
	(check_scope): Likewise.
	(value_of_root_1): Likewise.
	(varobj_value_get_print_value): Likewise.
	(varobj_editable_p): Likewise.
	(varobj_value_is_changeable_p): Likewise.
	(varobj_floating_p): Likewise.
	(varobj_default_value_is_changeable_p): Likewise.
	(varobj_invalidate_iter): Likewise.
	* varobj.h (struct varobj_update_result) <type_changed,
	children_changed, changed, value_installed>: Likewise.
	(struct varobj) <updated, frozen, not_fetched>: Likewise.
	(struct lang_varobj_ops) <value_is_changeable_p,
	value_has_mutated, is_path_expr_parent>: Likewise.
	(varobj_delete): Likewise.
	(varobj_set_frozen): Likewise.
	(varobj_get_frozen): Likewise.
	(varobj_set_value): Likewise.
	(varobj_update): Likewise.
	(varobj_editable_p): Likewise.
	(varobj_floating_p): Likewise.
	(varobj_has_more): Likewise.
	(varobj_is_dynamic_p): Likewise.
	(varobj_default_value_is_changeable_p): Likewise.
	(varobj_value_is_changeable_p): Likewise.
	(varobj_is_anonymous_child): Likewise.
	(varobj_default_is_path_expr_parent): Likewise.

gdb/ada-varobj.c

@@ -929,7 +929,7 @@ ada_value_of_variable (const struct varobj *var,
 
 /* Implement the "value_is_changeable_p" routine for Ada.  */
 
-static int
+static bool
 ada_value_is_changeable_p (const struct varobj *var)
 {
   struct type *type = var->value ? value_type (var->value) : var->type;
@@ -939,7 +939,7 @@ ada_value_is_changeable_p (const struct varobj *var)
     {
       /* This is in reality a pointer to an unconstrained array.
 	 its value is changeable.  */
-      return 1;
+      return true;
     }
 
   if (ada_is_string_type (type))
@@ -947,7 +947,7 @@ ada_value_is_changeable_p (const struct varobj *var)
       /* We display the contents of the string in the array's
 	 "value" field.  The contents can change, so consider
 	 that the array is changeable.  */
-      return 1;
+      return true;
     }
 
   return varobj_default_value_is_changeable_p (var);
@@ -955,7 +955,7 @@ ada_value_is_changeable_p (const struct varobj *var)
 
 /* Implement the "value_has_mutated" routine for Ada.  */
 
-static int
+static bool
 ada_value_has_mutated (const struct varobj *var, struct value *new_val,
 		       struct type *new_type)
 {
@@ -966,7 +966,7 @@ ada_value_has_mutated (const struct varobj *var, struct value *new_val,
      has mutated.  */
   if (ada_varobj_get_number_of_children (new_val, new_type)
       != var->num_children)
-    return 1;
+    return true;
 
   /* If the number of fields have remained the same, then we need
      to check the name of each field.  If they remain the same,
@@ -986,9 +986,9 @@ ada_value_has_mutated (const struct varobj *var, struct value *new_val,
     if (ada_varobj_get_name_of_child (new_val, new_type,
 				      var->name.c_str (), i)
 	!= var->children[i]->name)
-      return 1;
+      return true;
 
-  return 0;
+  return false;
 }
 
 /* varobj operations for ada.  */