Note the build profile in output by default

[alexcrichton]

This commit changes the "Compiling" message of cargo:

# old
Compiling foo v0.1.0

# new
Compiling (debug) foo v0.1.0

This change is aimed at preventing mistakenly thinking that cargo build
produces optimized binaries as well as providing a clear indication of whether
the build is a debug build or a release build.

Closes #1309

[rust-highfive]

r? @huonw

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[alexcrichton]

r? @wycats

cc @tanadeau, @tomjakubowski, @pornel

[kornelski]

LGTM :)

[tanadeau]

Could the descriptions be debug/unoptimized and release/optimized instead of just debug and release?

[alexcrichton]

Hm I don't want to add too much output and currently the names mirror the debug and release directories that the output is going into. I would personally lean towards a concise output and see where it takes us before adding yet more output indicating whether it is optimized or not.

[tanadeau]

@alexcrichton That makes sense. 👍

[nikomatsakis]

I personally appreciate having a clear indication what is being compiled and in what mode.

[bors]

☔️ The latest upstream changes (presumably #1373) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

No consensus was reached here and it seems that the necessity for this is far less now that we have target/debug and target/release, so I'm going to close this so that we may pursue this at a later date if necessary.