fix the mem leaks from makecstring()

source/texk/web2c/luatexdir/font/dofont.c

source/texk/web2c/luatexdir/font/luafont.c

source/texk/web2c/luatexdir/font/texfont.c

source/texk/web2c/luatexdir/font/tounicode.c

source/texk/web2c/luatexdir/font/vfovf.c

source/texk/web2c/luatexdir/lua/lnodelib.c

source/texk/web2c/luatexdir/lua/lstatslib.c

source/texk/web2c/luatexdir/lua/ltexlib.c

source/texk/web2c/luatexdir/lua/ltokenlib.c

source/texk/web2c/luatexdir/ocp/ocp.c

source/texk/web2c/luatexdir/ocp/readocp.c

source/texk/web2c/luatexdir/ocp/runocp.c

source/texk/web2c/luatexdir/pdf/pdfcolorstack.c

source/texk/web2c/luatexdir/pdf/pdfgen.c

source/texk/web2c/luatexdir/pdf/pdftables.c

source/texk/web2c/luatexdir/tex/filename.c

source/texk/web2c/luatexdir/tex/primitive.c

source/texk/web2c/luatexdir/tex/textoken.c

source/texk/web2c/luatexdir/utils/synctex.c