rustbuild: Build tests with LLD if use-lld = true was passed

[petrochenkov]

Addresses #76127 (comment).

Our test suite is generally ready to run with an explicitly specified linker (#45191),
so LLD specified with use-lld = true works as well.

Only 4 tests fail (on x86_64-pc-windows-msvc):

ui/panic-runtime/lto-unwind.rs
run-make-fulldeps/debug-assertions
run-make-fulldeps/foreign-exceptions
run-make-fulldeps/test-harness

All of them are legitimate issues with LLD (or at least with combination Rust+LLD) and manifest in segfaults on access to TLS (#76127 (comment)). UPD: These issues are caused by #72145 and appear because I had -Ctarget-cpu=native set.

UPD: Further commits build tests with LLD for non-MSVC targets and propagate LLD to more places when use-lld is enabled.

[rust-highfive]

r? @Mark-Simulacrum

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[mati865]

Could you also update this line?

rust/config.toml.example

Line 432 in 35fc835

# LLD will not be used if we're cross linking or running tests.

[petrochenkov]

Could you also update this line?

Done.

[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit 75a2c68 has been approved by Mark-Simulacrum

[bors]

⌛ Testing commit 75a2c68 with merge 25b2f48...

[rust-log-analyzer]

The job x86_64-apple of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

 Memory: 12 GB
Boot ROM Version: VMW71.00V.13989454.B64.1906190538
Apple ROM Info: [MS_VM_CERT/SHA1/27d66596a61c48dd3dc7216fd715126e33f59ae7]Welcome to the Virtual Machine
SMC Version (system): 2.8f0
Serial Number (system): VMWVz+YuxLFe
hw.ncpu: 4
hw.byteorder: 1234
hw.memsize: 12884901888
---
[TIMING] Compiletest { compiler: Compiler { stage: 2, host: TargetSelection { triple: "x86_64-apple-darwin", file: None } }, target: TargetSelection { triple: "x86_64-apple-darwin", file: None }, mode: "debuginfo", suite: "debuginfo", path: "src/test/debuginfo", compare_mode: None } -- 0.435
[TIMING] Compiletest { compiler: Compiler { stage: 2, host: TargetSelection { triple: "x86_64-apple-darwin", file: None } }, target: TargetSelection { triple: "x86_64-apple-darwin", file: None }, mode: "ui", suite: "ui-fulldeps", path: "src/test/ui-fulldeps", compare_mode: None } -- 0.489
[TIMING] Compiletest { compiler: Compiler { stage: 2, host: TargetSelection { triple: "x86_64-apple-darwin", file: None } }, target: TargetSelection { triple: "x86_64-apple-darwin", file: None }, mode: "rustdoc", suite: "rustdoc", path: "src/test/rustdoc", compare_mode: None } -- 0.371
[TIMING] Compiletest { compiler: Compiler { stage: 2, host: TargetSelection { triple: "x86_64-apple-darwin", file: None } }, target: TargetSelection { triple: "x86_64-apple-darwin", file: None }, mode: "pretty", suite: "pretty", path: "src/test/pretty", compare_mode: None } -- 0.390
thread 'main' panicked at 'fs::read_dir(builder.src.join("src/doc/book/redirects")) failed with No such file or directory (os error 2)', src/bootstrap/doc.rs:225:21
failed to run: /Users/runner/work/rust/rust/build/bootstrap/debug/bootstrap --stage 2 test
Build completed unsuccessfully in 0:00:07
== clock drift check ==
local time: Thu Sep 10 10:13:41 UTC 2020
local time: Thu Sep 10 10:13:41 UTC 2020
network time: Thu, 10 Sep 2020 10:13:41 GMT
== end clock drift check ==
##[error]Process completed with exit code 1.
Terminate orphan process: pid (2811) (sccache)
Terminate orphan process: pid (1817) (Python)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @rust-lang/infra. (Feature Requests)

[bors]

☀️ Test successful - checks-actions, checks-azure
Approved by: Mark-Simulacrum
Pushing 25b2f48 to master...