Move the libgccjit.so file in a target directory

[antoyo]

Since GCC is not multi-target, we need multiple libgccjit.so. Our solution to have a directory per target so that we can have multiple libgccjit.so.

r? @Kobzol

[rustbot]

This PR changes how GCC is built. Consider updating src/bootstrap/download-ci-gcc-stamp.

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo, @GuillaumeGomez

[rustbot]

Kobzol is not on the review rotation at the moment.
They may take a while to respond.

[rustbot]

This PR modifies tests/ui/issues/. If this PR is adding new tests to tests/ui/issues/,
please refrain from doing so, and instead add it to more descriptive subdirectories.

[antoyo]

@bjorn3: Is there any way to bless the UI tests for Aarch64 from an x86 computer?

[bjorn3]

You can try if ./x.py test tests/ui --target aarch64-unknown-linux-gnu --bless works.

[antoyo]

All these new test failures are due to the fact that --target is used and we now put libgccjit.so in a directory named after the target, so rustc_codegen_gcc doesn't find libgccjit.so.
Is this the correct way to ignore these tests?
Or are tests annotated with needs-llvm-compoments not expected to pass with a codegen that is not LLVM?

[bjorn3]

I think //@ ignore-backends: gcc makes sense. These tests would pass just fine with Cranelift if it is one of the targets supported by Cranelift. cg_clif always enables all backends of Cranelift.