increase the timeout for running rustc --version

[lovasoa]

Fixes #1312

[knight42]

I encounter this problem occasionally on my machine as well and I think it's safe to merge this PR.

[alexcrichton]

I'm sort of wary to merge this, what's causing rustc to take 10 seconds to prints its version?

[petrochenkov]

what's causing rustc to take 10 seconds to prints its version?

Guess: the toolchain is on a drive that's currently in low-power/low-noise mode and some wake up time is needed before rustc can be launched.

[Diggsey]

Couple of ideas:

• Make the time-out configurable, and if any binaries time-out, print a help message at the bottom explaining how to adjust the time-out.

• Try reading from the executable file before loading it, so we're not including the time taken to possibly spin up a drive.

[knight42]

@alexcrichton 10 secs may be too long, but 3 secs can be too short in some cases, like after a reboot:

>>> time rustc --version
rustc 1.24.0-nightly (b98fd524e 2018-01-05)
rustc --version  0.21s user 0.07s system 3% cpu 7.161 total
>>> time rustc --version
rustc 1.24.0-nightly (b98fd524e 2018-01-05)
rustc --version  0.18s user 0.03s system 99% cpu 0.208 total

[alexcrichton]

@bors: r+

Ok!

[bors]

📌 Commit 09a23b7 has been approved by alexcrichton

[bors]

⌛ Testing commit 09a23b7 with merge 5e60067...

[bors]

💥 Test timed out

[alexcrichton]

@bors: retry

[bors]

⌛ Testing commit 09a23b7 with merge fe1592b...

[bors]

💔 Test failed - status-travis

[alexcrichton]

@bors: retry

…

On Tue, Jan 9, 2018 at 10:39 AM, bors ***@***.***> wrote: 💔 Test failed - status-travis <https://travis-ci.org/rust-lang-nursery/rustup.rs/builds/326854977?utm_source=github_status&utm_medium=notification> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1313 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAD95P9s-8Bv8cvM5XdPRwBw-9MsJt6Kks5tI5ZLgaJpZM4REGf2> .

[bors]

⌛ Testing commit 09a23b7 with merge f2bd051...

[bors]

💔 Test failed - status-travis

[alexcrichton]

@bors: retry

…

On Tue, Jan 9, 2018 at 2:56 PM, bors ***@***.***> wrote: 💔 Test failed - status-travis <https://travis-ci.org/rust-lang-nursery/rustup.rs/builds/326893490?utm_source=github_status&utm_medium=notification> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1313 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAD95DPB_pe5y2462krZfwhs_ZJnoqD3ks5tI9JzgaJpZM4REGf2> .

[bors]

⌛ Testing commit 09a23b7 with merge 38e1d3a...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: alexcrichton
Pushing 38e1d3a to master...