Revert "Revert "Remove libbsd dependency for Linux""

[compnerd]

This reverts commit 4b87733.

[compnerd]

@benlangmuir -

15:30:10 FAILED: libdispatch-prefix/src/libdispatch-stamp/libdispatch-build libdispatch-prefix/lib/libdispatch.so libdispatch-prefix/lib/dispatch libdispatch-prefix/lib/libBlocksRuntime.so libdispatch-prefix/lib/BlocksRuntime 
15:30:10 cd /home/buildnode/jenkins/workspace/oss-swift-5.1-incremental-RA-linux-ubuntu-14_04/buildbot_incremental/swift-linux-x86_64/libdispatch-prefix/src/libdispatch-build && /opt/bin/cmake --build .
15:30:10 [0/1][  0%][0.000s] Re-running CMake...

Seems like it was an incremental build. It needs a clean build as some of the variables were still cached from the previous configure.

CC: @shahmishal - would be nice to actually get this restored along with a clean build on 14.04

[compnerd]

@swift-ci please test

[benlangmuir]

Sorry for the churn. Looks like this built fine last night on 14.04

[compnerd]

Seems that we got it merged back in quick enough, worked out just fine :-)

[ianpartridge]

Does this mean that Linux won't need the libbsd system package installed? If so, it would be great to get this in 5.1 so I can reduce the size of our Docker images even further. @compnerd?

[compnerd]

@ianpartridge - that is correct, Linux no longer requires the libbsd system package installed. I also updated the docs to reflect that. Also note that if you are trimming dependencies, libBlocksRuntime is no longer a dependency either.

[ianpartridge]

Awesome.