The ncurses development packages are going to see a change after the
Stretch release, ncursesw5-config will be replaced by ncursesw6-config.
Your package disables the ncurses frontend if ncursesw5-config is not
present on the build system. From my pbuilder log:
| checking for ncursesw5-config... no
| checking for ncurses - wide char support... no
| *** The ncursesw5-config script installed by ncursesw could not be found
| *** If ncursesw was installed in PREFIX, make sure PREFIX/bin is in
| *** your path, or set the NCURSES_CONFIG environment variable to the
| *** full path to ncursesw5-config.
| -- Frontends --
| - Curses No; missing libraries
The archlinux people did
sed -i 's/ncursesw5-config/ncursesw6-config/g' acinclude.m4
which obviously only works if
a) ncurses actually starts shipping ncursesw6-config, and
b) angband regenerates the configure script, e.g. with dh_autoreconf.