Previously zz wouldn't be able to compile anything using standard
modules like mem or log out of the box.
To fix this we copy the modules directory included in the source to
$out/share/zz/modules and add an entry to ZZ_MODULE_PATHS in the wrapper
around zz.
We also remove a search path entry which used to reference /build
because it used CARGO_MANIFEST_DIR at build time. The default search
path now includes:
* /nix/store/modules
* $out/share/zz/modules
* $(pwd)/modules
Patching out /nix/store/modules would be kind of cumbersome as it is a
multi-line entry, but it probably does no harm and fine to leave in.
An issue arising by this PR might be that the added search path entry
may take priority over an user specified location even though we use
--suffix. This is because zz internally uses a HashSet which has no
guaranteed iteration order. This may lead to unexpected behavior for
users wo previously provided custom versions of the standard modules via
ZZ_MODULE_PATHS. However, this is an issue in upstream issue as well
where ZZ_MODULE_PATHS may or may not take priority over the compiled in
search path, so this issue should probably be resolved upstream (I'll
file a report or PR).
The `platform` field is pointless nesting: it's just stuff that happens
to be defined together, and that should be an implementation detail.
This instead makes `linux-kernel` and `gcc` top level fields in platform
configs. They join `rustc` there [all are optional], which was put there
and not in `platform` in anticipation of a change like this.
`linux-kernel.arch` in particular also becomes `linuxArch`, to match the
other `*Arch`es.
The next step after is this to combine the *specific* machines from
`lib.systems.platforms` with `lib.systems.examples`, keeping just the
"multiplatform" ones for defaulting.
When cross compiling to the same kernel / arch combination, it is safe
to use strip of libraries. This happens when cross-compiling musl
programs. dontStrip is now set in each gcc compiler instead of in
gcc/builder.sh.
Fixes#75476
