Revert "Add optional signal forwarder and '-z' option to cli"

This CL breaks MIPS targets because they don't have SIGUNUSED
defined.

This reverts commit 74b902788f36b37c5dc9c283e535603784f40fc3.

Change-Id: Ica493149b5d5b93f492a5923721d332a7c5c9f95
3 files changed