fix dir backend code + dir related cleanups (HH)

source/texk/web2c/luatexdir/NEWS

source/texk/web2c/luatexdir/dvi/dvigen.w

source/texk/web2c/luatexdir/pdf/pdfshipout.w

source/texk/web2c/luatexdir/tex/buildpage.w

source/texk/web2c/luatexdir/tex/conditional.w

source/texk/web2c/luatexdir/tex/directions.h

source/texk/web2c/luatexdir/tex/directions.w

source/texk/web2c/luatexdir/tex/equivalents.h

source/texk/web2c/luatexdir/tex/linebreak.h

source/texk/web2c/luatexdir/tex/linebreak.w

source/texk/web2c/luatexdir/tex/maincontrol.w

source/texk/web2c/luatexdir/tex/packaging.w

source/texk/web2c/luatexdir/tex/scanning.w

source/texk/web2c/luatexdir/tex/texmath.w

source/texk/web2c/luatexdir/tex/texnodes.h

source/texk/web2c/luatexdir/tex/texnodes.w