Also begin to start work on cross compilation, though that will have to
be finished later.
The patches are based on the first version of
https://reviews.llvm.org/D99484. It's very annoying to do the
back-porting but the review has uncovered nothing super major so I'm
fine sticking with what I've got.
Beyond making the outputs work, I also strove to re-sync the packages,
as they have been drifting pointlessly apart for some time.
----
Other misc notes, highly incomplete
- lvm-config-native and llvm-config are put in `dev` because they are
tools just for build time.
- Clang no longer has an lld dep. That was introduced in
db29857eb391ed002046090851a44c452b80bdbd, but if clang needs help
finding lld when it is used we should just pass it flags / put in the
resource dir. Providing it at build time increases critical path
length for no good reason.
----
A note on `nativeCC`:
`stdenv` takes tools from the previous stage, so:
1. `pkgsBuildBuild`: `(?1, x, x)`
2. `pkgsBuildBuild.stdenv.cc`: `(?0, ?1, x)`
while:
1. `pkgsBuildBuild`: `(?1, x, x)`
2. `pkgsBuildBuild.targetPackages`: `(x, x, ?2)`
3. `pkgsBuildBuild.targetPackages.stdenv.cc`: `(?1, x, x)`
This reverts commit 0f25eb3e7dc1ad60288f95b7bc9ec8c7ce3959e5, reversing
changes made to df91ae1ac0733a5ad42411bc72826b4eee9e5111.
These toolchain changes are too problematic, so reverting for now; see
https://github.com/NixOS/nixpkgs/pull/107086#issuecomment-749196366
A port of #85925 for LLVM 11 to enable CFI for Chromium.
This is required for features such as `-fsanitize=cfi` that (by default)
load the file `…/resource-root/share/cfi_blacklist.txt`.
