The current target's ABI cannot be relied on for this.
For example, we may build the zig compiler for target
riscv64-linux-musl and provide a tarball for users to
download. A user could then run that zig compiler on
riscv64-linux-gnu. This use case is well-defined and
supported by Zig. But that means that we must detect
the system ABI here rather than
relying on `std.Target.current`.
Some C compilers, such as Clang, are known to rely on
argv[0] to find the path to their own executable,
without even bothering to resolve PATH. This results
in the message:
error: unable to execute command: Executable "" doesn't exist!
So we tell ChildProcess to expand argv[0] to the absolute path
to give them a helping hand.
when both `--cache on` and `--output-dir` parameters
are provided. This prevents re-linking `zig` with every
`make` even when `libzigstage2.a` was unchanged.
Rather than `zig0 build ...` the build now does
`zig0 build-lib ...`, avoiding the requirement of linking the build
script, and thus avoiding the requirement of finding native libc,
for systems where libc is the system ABI.
* 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.
See discussion here for context:
c6df5deb34 (comments)
Michael - I appreciate what you did here, making the configure script
work better for people in practice. When it was checking the build type
against a whitelist, I think it was worth it. However, now that we are
supporting systems which use non-standard cmake build modes, I don't
think this case-mismatch detection thing is worth it. It's starting to
get to the point where it's a lot of complication for very little
benefit. Besides, cmake is not case sensitive. If we support
non-standard build modes, then we would need to support a hypothetical
build mode of `release` (lower case).
So let's just remove this and rely on people to use the build system
correctly (like they will have to do when building any cmake project
from source).
