`std.zig.system.darwin.getSdk` now pulls only the SDK path
so we execute a child process only once and not twice as it was
until now since we parse the SDK version directly from the pulled path.
This is actually how `ld64` does it too.
These functions are problematic in light of dependencies because they
run and install, respectively, for the *owner* package rather than for
the *user* package. By removing these functions, the build script is
forced to provide the *Build object to associate the new step with,
making everything less surprising.
Unfortunately, this is a widely breaking change.
see #15079
Latest macOS 13.3 rolled out LLVM 15 and thus the way `nullptr_t` is
defined within the `libc++`:
157bbe6aea
This seems to require including `/usr/include` with `-isystem` directive
rather than `-I`. Otherwise we get clang miscompilation issues due to
missing `nullptr_t` declaration.
