Extend the capabilities of is_os to detect more platforms such as
freebsd and openbsd. Also remove `iswin()` helper function as it can be
replaced by `is_os("win")`.
vim-patch:8.2.1147: :confirm may happen in cooked mode
Problem: :confirm may happen in cooked mode. (Jason Franklin)
Solution: Switch to raw mode before prompting. (Brandon Pfeifer)
27321dbeed
Code is N/A, but this improves tests. Port the improved tests to Lua.
Problem: Integer overflow with large line number.
Solution: Check for overflow. (closesvim/vim#9202)
03725c5795
Put E1247 in globals.h as E1240 is also there.
Do not make getdigits() abort.