This is a bit simpler now, but more importantly it scales better when I
double the number of sorts of dependencies as part of my cross
compilation work.
Packages get --host and --target by default, but can explicitly request
any subset to be passed as needed. See docs for more info.
rustc: Avoid hash breakage by using the old (ignored)
dontSetConfigureCross when not cross building
This is especially useful when not cross compiling. It means we can
remove the `stdenv.isGlibc` predicate too.
Additionally, use this to simplify the logic to choose the
appropriate libiconv derivation.
`pkgsNoParams` was removed by me, but then #25035 was merged using it,
leading to an unbound identifier.
It would be nice to get travis to do build release-cross.nix or
something to catch these things.
In the extremely unlikely case that our store hash path ends in several
digits (as is the case right now), the Darwin ld will try to interpret
those digits as a version number and barf. To avoid that, we pass in the
SDK version explicitly to stop it from trying to figure it out from iffy
context.
See previous commit for what was done to `binutils` to make this
possible.
There were some uses of `forcedNativePackages` added. The
combination of overrides with that attribute is highly spooky: it's
often important that if an overridden package comes from it, the
replaced arguments for that package come from it. Long term this
package set and all the spookiness should be gone and irrelevant:
"Move along, nothing to see here!"
No hashes should be changed with this commit
Use `buildPackages.binutils` to get build = host != target binutils,
i.e. the old `binutilsCross`, and use
`buildPackages.buildPackages.binutils` to get build = host = target
binutils, i.e. the old `binutils`.
`buildPackages` chains like this are supposed to remove the need for
all such `*Cross` derivations. We start with binutils because it's
comparatively easy.
No hashes of cross-tests should be changed
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.
