Use standard bool types.

I'm using `stdbool.h` for the few remaining C files.  That will
have to change, soon.

src/url.hh

@@ -136,7 +136,7 @@ std::optional< std::string > a_Url_decode_hex_str(const char *str);
 std::optional< std::string > a_Url_encode_hex_str(const char *str);
 std::optional< std::string > a_Url_string_strip_delimiters(const char *str);
 int a_Url_host_type(const char *host);
-bool_t a_Url_same_organization(const DilloUrl &u1, const DilloUrl &u2);
+bool a_Url_same_organization(const DilloUrl &u1, const DilloUrl &u2);
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */