[nvim] Changes to vimrc and vimrc.common from long ago

vimrc

@@ -3,16 +3,16 @@
 
 source ~/.vimrc.common
 
-" Set this first for Vundle
 set nocompatible        " use enhanced vim features
 
-set backupdir=$VIM/backup
-                        " save backup files here
-set undodir=$VIM/undo   " save undo files here
+let s:localdir=expand("~/.local/vim")
+if !isdirectory(s:localdir)
+    call mkdir(s:localdir, "p")
+endif
 
-" Shared data file. The vim and nvim formats are incompatible so this needs to 
-" be set differently for vim and nvim.
-set viminfofile=$VIM/vim_shared_data
+let &backupdir=expand(s:localdir . "/backup//" . ",.")
+let &undodir=expand(s:localdir . "/undo//")
+let &viminfofile=expand(s:localdir . "/viminfo")
 
 " Shada data. Parameters as follows: (see :help shada)
 "   %   number of buffers to save and restore when no file argument is given