!!! Please attach the following file when filing a report to bugs.gentoo.org:
!!! /var/tmp/portage/sys-libs/ncurses-5.6-r2/work/narrowc/config.log

!!! ERROR: sys-libs/ncurses-5.6-r2 failed.
Call stack:
  ebuild.sh, line 1614:   Called dyn_compile
  ebuild.sh, line 971:   Called qa_call 'src_compile'
  environment, line 3354:   Called src_compile
  ncurses-5.6-r2.ebuild, line 50:   Called do_compile
  ncurses-5.6-r2.ebuild, line 74:   Called econf '--libdir=/lib' '--with-terminfo-dirs=/etc/terminfo:/usr/share/terminfo' '--with-shared' '--without-debug' '--without-profile' '--without-gpm' '--disable-termcap' '--enable-symlinks' '--with-rcs-ids' '--with-manpage-format=normal' '--enable-const' '--enable-colorfgbg' '--enable-echo' '--disable-warnings' '--without-assertions' '--with-leaks' '--without-expanded' '--with-macros' '--without-trace' '--with-chtype=long' '--with-mmask-t=long' '--disable-ext-colors' '--disable-ext-mouse'
  ebuild.sh, line 577:   Called die

!!! econf failed
!!! If you need support, post the topmost build error, and the call stack if relevant.
!!! A complete build log is located at '/var/tmp/portage/sys-libs/ncurses-5.6-r2/temp/build.log'.