Merge branch 'jk/parse-options-concat' into maint

Users of the parse_options_concat() API function need to allocate extra slots in advance and fill them with OPT_END() when they want to decide the set of supported options dynamically, which makes the code error-prone and hard to read. This has been corrected by tweaking the API to allocate and return a new copy of "struct option" array. * jk/parse-options-concat: parse_options: allocate a new array when concatenating