Revert 344389 "Revert r344375 "[Driver] check for exit code from SIGPIPE""

Summary:
Add preprocessor guards for UNIX.

This reverts commit r344389.

Reviewers: rnk, majnemer, jfb

Reviewed By: rnk

Subscribers: cfe-commits, pirama, srhines

Differential Revision: https://reviews.llvm.org/D53210

llvm-svn: 344536