We want code such as `(pkg.override {}).overrideScope (self: super: {})` to
work. This didn't work before, since `override` will call the original package
again, and the attribute `overideScope`, which `callPackageWithScope` added,
wasn't added again. The fix for this is to modify the package function itself
to include the `callPackageWithScope` attribute, so it'll be re-added whenever
the function is overriden for with arguments.
There is a small problem here though: since callPackage uses some magic
(`builtins.functionArgs`) to determine the auto-arguments of a function, we
can't just write `callPackageWith scope drvScope`, since
`builtins.functionArgs drvScope` will be `{}`. To fix this, we implement our own
`callPackageWith`.
Fixes https://github.com/NixOS/nixpkgs/issues/7953.
Closes https://github.com/NixOS/nixpkgs/pull/9336.
(this is reapplying 6b1957d17a, which got
lost in a merge)
Including apple_sdk.sdk is generally a recipe for a bad time on LLVM 3.8
and above, since you end up with bad headers in the wrong place that hurt
the new libc++ in 3.8 and above. In this case, qt only wanted the super-
generic SDK for CUPS headers, which we can just depend on directly now.
stdenv.cross is a silly attribute that needs to go leaving the well-defined hostPlatform and targetPlatform. This PR doesn't remove it, but changes its definition: before it tracked the target platform which is sometimes more useful for compilers, and now it tracks the host platform which is more useful for everything else. Most usages are libraries, falling in the "everything else" category, so changing the definition makes sense to appease the majority. The few compiler (gcc in particular) uses that exist I remove to use targetPlatform --- preserving correctness and becoming more explicit in the process.
I would also update the documentation aside mentioning stdenv.cross as deprecated, but the definition given actually erroneously assumes this PR is already merged!
Before all overrides were also pruned in the previous stage, now
only gcc and binutils are, because they alone care about about the
target platform. The rest of the overrides don't, so it's better to
preserve them in order to avoid spurious rebuilds.
The previous commit redefines `stdenv.cross` for the sake of normal
libaries, the most common use-case of that attribute. Some compilers
however relied on the old definition so we have them use
`targetPlatform` instead. This special casing is fine because we
eventually want to remove `stdenv.cross` and use either `hostPlatform`
or `targetPlatform` instead.
In practice, this is a strictly stronger condition than target != build
as we never have build = target != host. Really, the attribute should
be removed altogether, but for now we make it work for plain libraries,
which do not care about the target platform. In the few cases where the
compilers use this and actually care about the target platform, I'll
manually change them to use `targetPlatform` instead.
