(chroot) livecd src # emerge screen
Calculating dependencies... done!

>>> Emerging (1 of 1) app-misc/screen-4.0.2-r5 to /
 * screen-4.0.2.tar.gz MD5 ;-) ...                                                                                                                      [ ok ]
 * screen-4.0.2.tar.gz RMD160 ;-) ...                                                                                                                   [ ok ]
 * screen-4.0.2.tar.gz SHA1 ;-) ...                                                                                                                     [ ok ]
 * screen-4.0.2.tar.gz SHA256 ;-) ...                                                                                                                   [ ok ]
 * screen-4.0.2.tar.gz size ;-) ...                                                                                                                     [ ok ]
 * checking ebuild checksums ;-) ...                                                                                                                    [ ok ]
 * checking auxfile checksums ;-) ...                                                                                                                   [ ok ]
 * checking miscfile checksums ;-) ...                                                                                                                  [ ok ]
 * checking screen-4.0.2.tar.gz ;-) ...                                                                                                                 [ ok ]
>>> Unpacking source...
>>> Unpacking screen-4.0.2.tar.gz to /var/tmp/portage/screen-4.0.2-r5/work
 * Applying screen-4.0.1-int-overflow-fix.patch ...                                                                                                     [ ok ]
 * Applying screen-4.0.1-vsprintf.patch ...                                                                                                             [ ok ]
 * Applying 4.0.2-no-utempter.patch ...                                                                                                                 [ ok ]
 * Applying 4.0.2-no-libelf.patch ...                                                                                                                   [ ok ]
 * Applying 4.0.2-64bit-time.patch ...                                                                                                                  [ ok ]
 * Applying 4.0.2-windowlist-multiuser-fix.patch ...                                                                                                    [ ok ]
 * Applying 4.0.2-nonblock.patch ...                                                                                                                    [ ok ]
 * Running autoconf ...                                                                                                                                 [ !! ]

 * Failed Running autoconf !
 *
 * Include in your bugreport the contents of:
 *
 *   /var/tmp/portage/screen-4.0.2-r5/temp/autoconf-22266.out


!!! ERROR: app-misc/screen-4.0.2-r5 failed.
Call stack:
  ebuild.sh, line 1543:   Called dyn_unpack
  ebuild.sh, line 707:   Called src_unpack
  screen-4.0.2-r5.ebuild, line 73:   Called eautoconf
  autotools.eclass, line 137:   Called autotools_run_tool 'autoconf'
  autotools.eclass, line 193:   Called die

!!! Failed Running autoconf !
!!! If you need support, post the topmost build error, and the call stack if relevant.