gnulib-tool.py: Fix some code generation details. * pygnulib/GLEmiter.py: Don't produce Windows CR-LFs on Windows. (GLEmiter.po_Makevars): Emit a definition of top_builddir, not top_subdir. (GLEmiter.po_POTFILES_in): Fix result when sourcebase is 'tests' or something like that. (GLEmiter.initmacro_start): Add two more newlines (mistake from 2021-04-11).