* libc_installation.cpp is deleted.
src-self-hosted/libc_installation.zig is now used for both stage1 and
stage2 compilers.
* (breaking) move `std.fs.File.access` to `std.fs.Dir.access`. The API
now encourages use with an open directory handle.
* Add `std.os.faccessat` and related functions.
* Deprecate the "C" suffix naming convention for null-terminated
parameters. "C" should be used when it is related to libc. However
null-terminated parameters often have to do with the native system
ABI rather than libc. "Z" suffix is the new convention. For example,
`std.os.openC` is deprecated in favor of `std.os.openZ`.
* Add `std.mem.dupeZ` for using an allocator to copy memory and add a
null terminator.
* Remove dead struct field `std.ChildProcess.llnode`.
* Introduce `std.event.Batch`. This API allows expressing concurrency
without forcing code to be async. It requires no Allocator and does
not introduce any failure conditions. However it is not thread-safe.
* There is now an ongoing experiment to transition away from
`std.event.Group` in favor of `std.event.Batch`.
* `std.os.execvpeC` calls `getenvZ` rather than `getenv`. This is
slightly more efficient on most systems, and works around a
limitation of `getenv` lack of integration with libc.
* (breaking) `std.os.AccessError` gains `FileBusy`, `SymLinkLoop`, and
`ReadOnlyFileSystem`. Previously these error codes were all reported
as `PermissionDenied`.
* Add `std.Target.isDragonFlyBSD`.
* stage2: access to the windows_sdk functions is done with a manually
maintained .zig binding file instead of `@cImport`.
* Update src-self-hosted/libc_installation.zig with all the
improvements that stage1 has seen to src/libc_installation.cpp until
now. In addition, it now takes advantage of Batch so that evented I/O
mode takes advantage of concurrency, but it still works in blocking
I/O mode, which is how it is used in stage1.
Andrew Kelley