stage2: ensure builtin packages are always available

[nektro]

after a certain package depth, it appears access to the 'std' package is lost. with this fix building nektro/aquila reaches a new error

[nix-shell:~/other/dev/aquila]$ ~/other/dev/zig/zig-out/bin/zig build --prominent-compile-errors -fno-stage1
/home/meg/other/dev/aquila/.zigmod/deps/git/github.com/nektro/zig-zorm/src/sqlite3.zig:1:21: error: unable to open 'std': PackageNotFound
const std = @import("std");
                    ^
aquila...The step exited with error code 1
error: the build command failed with exit code 1

[nix-shell:~/other/dev/aquila]$ ~/other/dev/zig/zig-out/bin/zig build --prominent-compile-errors -fno-stage1
Semantic Analysis [2456] ensureTotalCapacityPrecise... thread 78535 panic: integer overflow
/home/meg/other/dev/zig/lib/std/mem.zig:3045:54: 0x2dd642a in std.mem.alignForwardGeneric (zig)
    return alignBackwardGeneric(T, addr + (alignment - 1), alignment);
                                                     ^
/home/meg/other/dev/zig/src/codegen/llvm.zig:2651:57: 0x30e8575 in codegen.llvm.DeclGen.lowerType (zig)
                    offset = std.mem.alignForwardGeneric(u64, offset, field_align);
                                                        ^
/home/meg/other/dev/zig/src/codegen/llvm.zig:2376:43: 0x30df435 in codegen.llvm.DeclGen.resolveGlobalDecl (zig)
        const llvm_type = try dg.lowerType(decl.ty);
                                          ^
/home/meg/other/dev/zig/src/codegen/llvm.zig:3740:39: 0x30ef167 in codegen.llvm.DeclGen.lowerDeclRefValue (zig)
            try self.resolveGlobalDecl(decl_index);
                                      ^
....

[ifreund]

This doesn't feel like the right fix, why is the std package not found "after a certain package depth"?

[Vexu]

std and builtin are only added to first level packages in

zig/src/Compilation.zig

Line 1468 in b66247c

while (other_pkg_iter.next()) |pkg| {

Either that needs to be made recursive or builtin should also be handled here. Also is root intentionally omitted from other packages?

[ifreund]

If I'm not mistaken, this change would make the code Vexu referenced in Compilation.zig unnecessary. It should probably be removed.

[ifreund]

Also is root intentionally omitted from other packages?

It's used with the std package, so I think it is intended to be available outside of the root package.

[nektro]

just to be sure, 'root' is mod.main_pkg right?

[nektro]

fail seems unrelated?

[andrewrk]

Let's let the CI run; I can do the typo fix upon merging.

[andrewrk]

Suggested change

	fatal("unable to add package '{s}' -> '{s}': conflicts with builtin pacakge", .{ pkg_name.?, pkg_path.? });
	fatal("unable to add package '{s}' -> '{s}': conflicts with builtin package", .{ pkg_name.?, pkg_path.? });