libyang FEATURE introduce and use new ly_bool type

To indicate simple flags or true/false return values, use a standalone
ly_bool type.

We do not use stdbool's bool type to avoid need to mimic all its
features on platforms that do not provide it. ly_bool is just a simple
rename for uint8_t and the reason to use it is only a better readability
of the meaning of the variables or function's return values.
diff --git a/src/printer_xml.c b/src/printer_xml.c
index a90b012..3b92a9f 100644
--- a/src/printer_xml.c
+++ b/src/printer_xml.c
@@ -140,11 +140,11 @@
     const char **prefs, **nss;
     const char *xml_expr = NULL, *mod_name;
     uint32_t ns_count, i;
-    uint8_t rpc_filter = 0;
+    ly_bool rpc_filter = 0;
     char *p;
     size_t len;
 #endif
-    uint8_t dynamic;
+    ly_bool dynamic;
 
     /* with-defaults */
     if (node->schema->nodetype & LYD_NODE_TERM) {
@@ -288,7 +288,7 @@
 xml_print_term(struct xmlpr_ctx *ctx, const struct lyd_node_term *node)
 {
     struct ly_set ns_list = {0};
-    uint8_t dynamic;
+    ly_bool dynamic;
     const char *value;
 
     xml_print_node_open(ctx, (struct lyd_node *)node);