Prior to this change, builtins would take their arguments as `wchar_t **`.
This implies that the order of the arguments may be changed (which is
true, `wgetopter` does so) but also that the strings themselves may be
changed, which no builtin should do.
Switch them all to take `const wchar_t **` instead: now the arguments may
be rearranged but their contents may no longer be modified.
`streams.out.push_back` for fd_streams_t writes to the
fd *immediately*. We might want to introduce a general buffering
strategy, but in this case writing it in one go is the simplest and
seems acceptable - we already have constrained the argument size, so
just pushing it out should work well enough.
See #7836
A weird interaction between grouped short options and our weird option
parsing that puts unknown options back:
```
echo "-n foo"
```
would see the `-n`, turn off printing newlines, interpret the " " as
another grouped short option, see that there is no short option for
space and put the entire token back on the arguments pile.
So it would print "-n foo" *without a newline*.
Fix this by keeping an old state of the options around and reverting
it when putting options back.
The alternative is *probably* to forbid the " " short option in
wgetopt, then check if an option group contains it and error out, but
this should only really be a problem in `echo` because that is,
AFAICT, the only thing that puts the options back.
Fixes#7614
This runs build_tools/style.fish, which runs clang-format on C++, fish_indent on fish and (new) black on python.
If anything is wrong with the formatting, we should fix the tools, but automated formatting is worth it.
While supported by gcc and clang, \e is a gcc-specific extension and not
formally defined in the C or C++ standards.
See [0] for a list of valid escapes.
[0]: https://stackoverflow.com/a/10220539/17027
Running the tests on travis revealed that some compilers (or at least
with some options) call the wrong struct constructor if there is more
than one struct with the same name but differing definitions.
