vim wasn't linking against ncurses (#3838)

See #3829.  Vim's configure was searching for ncurses
instead of ncursesw.

var/spack/repos/builtin/packages/vim/package.py

@@ -90,6 +90,8 @@ def configure_args(self):
 
         configure_args = ["--enable-fail-if-missing"]
 
+        configure_args.append("--with-tlib=ncursesw")
+
         configure_args.append("--with-features=" + feature_set)
 
         if '+python' in spec: