Avoid use of \protected@edef when in 'generic' mode


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@4737 de43f980-851b-0410-b2f7-c40aca1f87e0
Improved version of \__dim_strip_bp:n (thanks to HO)


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@4738 de43f980-851b-0410-b2f7-c40aca1f87e0