Refactor the using of bool type

src/__internal/include.h

@@ -31,8 +31,8 @@
 #  define nullptr ((void*)0)
 #endif
 
-#define true  ((_Bool)1)
-#define false ((_Bool)0)
+#define true  ((bool)1)
+#define false ((bool)0)
 
 #define abs(v) _Generic((v), ldbl_t: fabsl, dbl_t: fabs, fl_t: fabsf)(v)
 

src/__internal/vnode.h

@@ -9,7 +9,7 @@
 #define is_permissible(T) (sizeof(void*) >= sizeof(T) && _Alignof(void*) >= _Alignof(T))
 
 typedef union {
-    void* ptr; _Bool   b;
+    void* ptr; bool    b;
     str_t   s; arr_t   a; list_t  l;
     map_t   m; set_t  vs;
     u8_t   u8; u16_t u16; u32_t u32; u64_t u64;