Problem:    Wrong argument for append() gives two error messages.
Solution:   When getting an error for a number argument don't try using it as
            a string. (closes vim/vim#11335)
https://github.com/vim/vim/commit/801cd35e7e3b21e519e12a1610ee1d721e40893e

Skip test as it depends on too many previous patches.

Problem:    Wrong column when calling setcursorcharpos() with zero lnum.
Solution:   Set the line number before calling buf_charidx_to_byteidx().
            (closes vim/vim#11329)
https://github.com/vim/vim/commit/79f234499b6692cc16970b7455bc9b002242632f

Problem:    Error for line number in legacy script.
Solution:   Check for number type.
https://github.com/vim/vim/commit/f6bdd82c7e2076dbacb764a5d288189d61c68451

N/A patches for version.c:

vim-patch:8.2.2670: Vim9: error for append(0, text)

Problem:    Vim9: error for append(0, text).
Solution:   Check for negative number. (closes vim/vim#8022)
https://github.com/vim/vim/commit/b2ac7d0663ef31a335c50c6afca042ed9ace5059

Problem:    Vim9: no error when using "2" for a line number.
Solution:   Give an error message if the line number is invalid. (closes vim/vim#7492)
https://github.com/vim/vim/commit/9a963377b4811e4e0419ec8825856ff4b01331ac

N/A patches for version.c:

vim-patch:8.2.1465: Vim9: subscript not handled properly

Problem:    Vim9: subscript not handled properly.
Solution:   Adjust error message.  Remove dead code.  Disallow string to
            number conversion in scripts.
https://github.com/vim/vim/commit/56acb0943ede35cd9d2f6667cde2442819ccbf59

Problem:    Vim9: cannot list a lambda function.
Solution:   Support the <lambda>9 notation, like :disassemble. (closes vim/vim#7634)
https://github.com/vim/vim/commit/b657198cb30765468451d7f68fce49b5b4000c5d

refactor: replace unnecessary helper functions in optionstr.c

Add -Wno-strict-prototypes flag to external dependencies to suppress
cjson warnings. These needs to be fixed upstream first.

Replaces unnecessary helper functions in `optionstr.c` such as
`get_option_flags()`, `get_option_fullname()`, `set_option_flag()`,
`is_global_option()`, etc. with a single `get_option()` helper function
that allows direct access to the `options` array.

Also refactors `f_exists()` to use `get_varp_scope` instead of using
`get_option_tv`. This opens up the path for removing `getoptions_T`
altogether later down the line since the hidden option logic is no
longer needed.

Co-authored-by: bfredl <bjorn.linse@gmail.com>
Co-authored-by: Christian Clason <c.clason@uni-graz.at>