the curses configure checks fail if only /usr/include/ncursesw/curses.h is installed (on a Debian/Ubuntu system, uninstall the libncurses5-dev package, and install the libncursesw5-dev package).

The attached patch adds -I/usr/include/ncursesw to CPPFLAGS for the tests.

I assume that most buildbot systems still have an /usr/include/curses.h installed, so the tests do the intended thing, because the features tested are the same in ncurses and ncursesw, but basically the wrong headers are used for these tests if both /usr/include/curses.h and /usr/include/ncursesw/curses.h are installed.