Assuming you are building a custom kernel ala http://fedoraproject.org/wiki/Docs/CustomKernel
If I remove ncurses-devel and do make menuconfig, I get the same error (FC14 x86_64). Once I install it is happy again.
Hacking on the scripts by adding an 'echo' and 'ldd' to get some info -- i.e. modifying scripts/kconfig/lxdialog/check-lxdialog.sh so that lines 38-45 look like this:
echo $cc -xc - -o $tmp
$cc -xc - -o $tmp 2>/dev/null <<'EOF'
if [ $? != 0 ]; then
gives this output:
gcc -I/usr/include/ncurses -DCURSES_LOC=<ncurses.h> -DLOCALE -lncursesw -xc - -o .lxdialog.tmp
linux-vdso.so.1 => (0x00007fff44310000)
libncursesw.so.5 => /lib64/libncursesw.so.5 (0x0000003688a00000)
libtinfo.so.5 => /lib64/libtinfo.so.5 (0x0000003697400000)
libc.so.6 => /lib64/libc.so.6 (0x0000003685600000)
libdl.so.2 => /lib64/libdl.so.2 (0x0000003685e00000)
which doesn't shed much light on the problem since /usr/include/ncurses/ncurses.h and /usr/lib64/ncursesw.so are included in ncurses-devel and /lib64/libncursesw.so.5 is provided by ncurses-lib.
Not sure what is going on unless for some strange reason it wants ncurses-devel.i686 and ncurses-lib.i686 for your build (I only needed the x86_64 version here).