…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? `@Mark-Simulacrum` cc `@camelid`

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? ``@Mark-Simulacrum`` cc ``@camelid``

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? ```@Mark-Simulacrum``` cc ```@camelid```

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? ````@Mark-Simulacrum```` cc ````@camelid````

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? `````@Mark-Simulacrum````` cc `````@camelid`````

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? ``````@Mark-Simulacrum`````` cc ``````@camelid``````

…k-Simulacrum

Add `download-rustc = "if-unchanged"`

This allows keeping the setting to a fixed value without having to
toggle it when you want to work on the compiler instead of on tools.

This sets `BOOTSTRAP_DOWNLOAD_RUSTC` in bootstrap.py so rustbuild doesn't have to try and replicate its logic.

Helps with rust-lang#81930.

r? ```````@Mark-Simulacrum``````` cc ```````@camelid```````

Rollup of 5 pull requests

Successful merges:

 - rust-lang#83368 (Add `download-rustc = "if-unchanged"`)
 - rust-lang#83705 (Give a better error when --theme is not a CSS file)
 - rust-lang#83853 (Disallow the use of high byte registes as operands on x86_64)
 - rust-lang#83877 (Remove unnecessary exceptions to the platform-specific code check)
 - rust-lang#83878 (Fix racing file access in tidy)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Add `x.py setup tools` which enables `download-rustc` by default

Helps with rust-lang#81930. I know I said in that issue that I should fix that rebasing rebuilds bootstrap, but the compile time improvement is so good I think it's ok to leave that fix for later (I still plan to work on it). I think all the outright bugs have been fixed :)

This builds on rust-lang#83368 so I can set the option to `if-unchanged`.

r? `@Mark-Simulacrum`

Add `x.py setup tools` which enables `download-rustc` by default

Helps with rust-lang#81930. I know I said in that issue that I should fix that rebasing rebuilds bootstrap, but the compile time improvement is so good I think it's ok to leave that fix for later (I still plan to work on it). I think all the outright bugs have been fixed :)

This builds on rust-lang#83368 so I can set the option to `if-unchanged`.

r? ``@Mark-Simulacrum``

Add `x.py setup tools` which enables `download-rustc` by default

Helps with rust-lang#81930. I know I said in that issue that I should fix that rebasing rebuilds bootstrap, but the compile time improvement is so good I think it's ok to leave that fix for later (I still plan to work on it). I think all the outright bugs have been fixed :)

This builds on rust-lang#83368 so I can set the option to `if-unchanged`.

r? ```@Mark-Simulacrum```