doc: Small updates.
* DEPENDENCIES: Document --with-libncurses-prefix instead of
--with-ncurses-prefix, since that is what the option would be if
AC_LIB_LINKFLAGS_BODY([ncurses]) was actually in use.
* HACKING: Stop suggesting Java 7 implementations, since Java 7 support has
ended. Suggest to create 3 more locales, needed to avoid SKIPs of gnulib tests.
