rustc --print crashes for some options when piped into a process not listening on STDIN

[mcdenhoed]

Some options for the command rustc --print cause a panic when the output of the command is piped into a process not listening for input on STDIN.

Steps to Reproduce

The following commands will crash:

• rustc --print cfg | echo "test"
• rustc --print target-list | echo "test"
• rustc --print relocation-models | echo "test"
• rustc --print code-models | echo "test"

Meta

I've seen this in the following versions:

• rustc 1.22.0-nightly (dead08cb3 2017-09-08) running on x86_64-apple-darwin
• rustc 1.20.0 (f3d6973f4 2017-08-27) running on x86_64-apple-darwin

[zackmdavis]

Duplicate of #34376?

[sfackler]

Yep, closing as a dupe of #34376.