Dosemu 1.4.0 compiles and works on x86-64 system. Keyword ~amd64 should be added to the ebuild.
Just in case: emerge --info : Portage 2.1.2.2 (default-linux/amd64/2006.1, gcc-4.1.1, glibc-2.5-r2, 2.6.18-gentoo-r6 x86_64) ================================================================= System uname: 2.6.18-gentoo-r6 x86_64 AMD Athlon(tm) 64 Processor 2800+ Gentoo Base System release 1.12.9 Timestamp of tree: Wed, 09 May 2007 10:00:01 +0000 ccache version 2.4 [disabled] dev-java/java-config: 1.3.7, 2.0.31-r5 dev-lang/python: 2.4.3-r4 dev-python/pycrypto: 2.0.1-r5 dev-util/ccache: 2.4-r7 sys-apps/sandbox: 1.2.17 sys-devel/autoconf: 2.13, 2.61 sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10 sys-devel/binutils: 2.16.1-r3 sys-devel/gcc-config: 1.3.16 sys-devel/libtool: 1.5.22 virtual/os-headers: 2.6.17-r2 ACCEPT_KEYWORDS="amd64" AUTOCLEAN="yes" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=athlon64 -O2 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config" CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/java-config/vms/ /etc/revdep-rebuild /etc/terminfo /etc/texmf/web2c" CXXFLAGS="-march=athlon64 -O2 -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="distlocks metadata-transfer sandbox sfperms strict" GENTOO_MIRRORS="http://pandemonium.tiscali.de/pub/gentoo/ ftp://cesium.di.uminho.pt/pub/gentoo/ http://ftp.gentoo.or.kr/ ftp://pandemonium.tiscali.de/pub/gentoo/ ftp://ftp.isu.edu.tw/pub/Linux/Gentoo http://ftp.isu.edu.tw/pub/Linux/Gentoo http://mirror.gentoo.gr.jp http://gentoo.cites.uiuc.edu/pub/gentoo/ http://mirror.usu.edu/mirrors/gentoo/ ftp://ftp.du.se/pub/os/gentoo" LANG="ru_RU.UTF-8" LC_ALL="ru_RU.UTF-8" LINGUAS="ru en" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-*" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="7zip X alsa amd64 berkdb bitmap-fonts cairo cli cracklib crypt cups curl doc dri flac fortran gdbm gif gpm iconv isdnlog jpeg kde libg++ midi mp3 ncurses nls nptl nptlonly ogg opengl pam pcre perl png ppds pppd python qt qt3 qt4 readline reflection sdl sdl-sound session slang spl ssl svg tcpd tiff timidity truetype truetype-fonts type1-fonts unicode userlocales vorbis xorg xpm zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="ru en" USERLAND="GNU" VIDEO_CARDS="apm ark ati chips cirrus cyrix dummy fbdev glint i128 i810 mga neomagic nv rendition s3 s3virge savage siliconmotion sis sisusb tdfx tga trident tseng v4l vesa vga via vmware voodoo" Unset: CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LDFLAGS, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, PORTDIR_OVERLAY
*** Bug 178118 has been marked as a duplicate of this bug. ***
Done.