The sockaddr pointer and size of the accept function points to a data structure that can only be determined at runtime. The only requirement is that it must be large enough to hold 2 bytes for the address family value. Typeical usage of the socket API is for UDP/TCP IPv4 and IPv6 sockets, which use sockaddr_in and sockaddr_in6. And some sockets can actually support both simultaneously in which case the app may want to have access to the size of the returned sockaddr. Operating systems can even support custom protocols where they use custom sockaddr data structures. In this case the standard library would have no knowledge of the actual size of the sockaddr being passed into the accept function. In this case the standard library should defer to the app to pass in the size of their structure.
* `std.os.execve` had the wrong name; it should have been
`std.os.execvpe`. This is now corrected.
* introduce `std.os.execveC` which does not look at PATH, and uses
null terminated parameters, matching POSIX ABIs. It does not
require an allocator.
* fix typo nonsense doc comment in `std.fs.MAX_PATH_BYTES`.
* introduce `std.os.execvpeC`, which is like `execvpe` except it
uses null terminated parameters, matching POSIX ABIs, and thus
does not require an allocator.
* `std.os.execvpe` implementation is reworked to only convert
parameters and then delegate to `std.os.execvpeC`.
* `std.os.execvpeC` improved to handle `ENOTDIR`. See #3415
