Set \newlinechar for l3build

If we are imagining this might get used with plain then we need the right
new line char!


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@5004 de43f980-851b-0410-b2f7-c40aca1f87e0
Keep 'regression-test' as the extracted code name


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@5005 de43f980-851b-0410-b2f7-c40aca1f87e0
The build stuff only requires the basic DocStrip program


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@5006 de43f980-851b-0410-b2f7-c40aca1f87e0