So we still have some issues with the GUI clipboard.
My hypothesis is that because nvim is caching the has_clipboard static variable then the clipboard will always be considered as
invalid and can NEVER be enabled.
Test setup
First I'm going to start nvim in a way that prevents any clipboard for working by changing the PATH.
... even if packages for lua and all deps(mpack, bitop, lpeg) are installed. This seems to be a problem with the lua binary name
in OpenBSD its called lua51, lua52, luajit51 - instead of the expected lua5.1 or just lua.
Vim's system('string') interface is not always straightforward in Windows,
its behaviour can be downright unexpected involves an intricate set of options. Its primary purpose its to execute
a command in the shell (see &shell) in simple terms we can think that calling system('some command') is equivalent
to spawning a process with the following arguments
[&shell, &shellcmdflag, 'some command']
and sometimes this might be true but it also might not. Consider the following examples (I'm running in gVim 7.4/Windows 8)
This could lead to the misconception that, for example, executable("file.bat") being 1 implies that system(["file.bat"]) is expected to succeed, which is not true. But this is an issue with system([]) in windows and not with executable(). The notion of executable in Windows is fundamentaly a shell concept, because unlike UNIX there no notion of shebang and permission bits, that allows execution of non binary files.