Bug#54569 Some options are not allowed to take argument when passed with loose- prefix

Boolean options cause parsing failures when they are given
with prefix loose- and an argument, either in the command
line or in configuration file.

The reason was a faulty logic which forced the parsing
to throw an error when an argument of type NO_ARG was
used together with an argument which has been identified
as a key-value pair. Despite the attribute NO_ARG these
options actually take arguments if they are of type
BOOL.

include/my_getopt.h

@@ -39,6 +39,13 @@ C_MODE_START
 #define GET_ASK_ADDR	 128
 #define GET_TYPE_MASK	 127
 
+/**
+  Enumeration of the my_option::arg_type attributes.
+  It should be noted that for historical reasons variables with the combination
+  arg_type=NO_ARG, my_option::var_type=GET_BOOL still accepts
+  arguments. This is someone counter intuitive and care should be taken
+  if the code is refactored.
+*/
 enum get_opt_arg_type { NO_ARG, OPT_ARG, REQUIRED_ARG };
 
 struct st_typelib;