package/ncurses: Allow building wide char support

Allow ncurses to be configured with wide char support; this causes the
libraries to be built with the 'w' suffix (eg libncursesw.so,
libmenuw.so, etc), so we need to create a few symlinks.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>