Log Message:
Update package to 8.0.0021.

Patches:
8.0.0001  intro screen still mentions version7
8.0.0002  the netrw plugin does not work
8.0.0003  getwinvar() returns wrong Value of boolean and number options
8.0.0004  error messagge of function() with wrong argument says NULL
8.0.0005  netbeans test fails with Python 3
8.0.0006  ":lb" is interpreted as ":lbottom" instead of \ 
":lbuffer"
8.0.0007  Vim 7.4 is still mentioned in a few places
8.0.0008  popup complete test is disabled
8.0.0009  unnecessary workaround for AppVeyor
8.0.0010  crash when editing file that starts with crypt header
8.0.0011  on OSX Test_pipe_through_sort_all() sometimes fails
8.0.0012  typos in comments
8.0.0013  (after 8.0.0011) missing comma in list
8.0.0014  crypt tests are old style
8.0.0015  can't tell which part of a channel has "buffered" status
8.0.0016  (after 8.0.0015) build fails
8.0.0017  cannot get the number of current quickfix or location list
8.0.0018  when using ":sleep" channel input is not handled
8.0.0019  test_command_count is old style
8.0.0020  the regexp engines are not reentrant
8.0.0021  GUI: cursor may be drawn on second half of double byte char

pkgsrc changes:
- switch to github to provide tarballs
- some minor changes