Bugzilla Bug 150323

dev-util/csup works in ~x86

confirming, emerges fine on my ~x86 system.

emerge --info
Portage 2.1.2_pre2-r5 (default-linux/x86/2006.1/desktop, gcc-4.1.1,
glibc-2.4-r4, 2.6.19-rc1 i686)
=================================================================
System uname: 2.6.19-rc1 i686 Intel(R) Pentium(R) M processor 1600MHz
Gentoo Base System version 1.12.5
Last Sync: Sat, 07 Oct 2006 10:50:01 +0000
ccache version 2.4 [disabled]
app-admin/eselect-compiler: [Not Present]
dev-java/java-config: 1.3.7, 2.0.30
dev-lang/python:     2.3.5-r3, 2.4.3-r4
dev-python/pycrypto: 2.0.1-r5
dev-util/ccache:     2.4-r6
dev-util/confcache:  [Not Present]
sys-apps/sandbox:    1.2.18.1
sys-devel/autoconf:  2.13, 2.60
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2
sys-devel/binutils:  2.17
sys-devel/gcc-config: 1.3.13-r4
sys-devel/libtool:   1.5.22
virtual/os-headers:  2.6.17-r1
ACCEPT_KEYWORDS="x86 ~x86"
AUTOCLEAN="yes"
CBUILD="i686-pc-linux-gnu"
CFLAGS="-O2 -march=pentium-m -fomit-frame-pointer -pipe"
CHOST="i686-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="-O2 -march=pentium-m -fomit-frame-pointer -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig collision-protect distlocks fixpackages metadata-transfer
parallel-fetch sandbox sfperms strict userfetch userpriv usersandbox"
GENTOO_MIRRORS="http://mirror.switch.ch/mirror/gentoo/ http://gentoo.inode.at/"
LANG="en_GB.utf8"
LC_ALL="en_GB.utf8"
LINGUAS="en de en_GB"
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"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage/normal
/usr/local/portage/java-experimental"
SYNC="rsync://192.168.2.1/gentoo-portage"
USE="x86 X a52 aac acpi alsa apache2 bash-completion beagle berkdb bidi
bitmap-fonts bzip2 cairo cdr clamav cli crypt css cups curl dbus divx
divx4linux dlloader dri dts dvd dvdr dvdread eds elibc_glibc emboss encode
ethereal exif ffmpeg firefox font-server fortran freetype gcj gd gdbm gif gnome
gnuplot gnutls gphoto2 gpm graphviz gs gstreamer gtk hal hardenedphp ieee1394
imagemagick input_devices_evdev input_devices_keyboard input_devices_mouse
input_devices_synaptics ipod ipv6 isdnlog java jikes jpeg kde kdeenablefinal
kernel_linux libclamav libg++ linguas_de linguas_en linguas_en_GB live
logitech-mouse mad maildir mikmod mmx mono mozcalendar mozdevelop mozilla
mozsvg mp3 mpeg ncurses network nls no-htdocs nptl nptlonly ntfs nvidia oav ogg
oggvorbis opengl oss pam pcre pdf perl png ppds pppd python qt qt3 qt4
quicktime readline real reflection ruby samba screen sdl session spell spl sse
sse2 ssl stream subversion svg tcpd tetex theora threads tiff truetype
truetype-fonts type1-fonts udev unicode usb userland_GNU vcd video_cards_radeon
vlm vorbis wifi win32codecs wxwindows xcomposite xine xinerama xml2 xorg xprint
xv xvid zlib"
Unset:  CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LDFLAGS,
PORTAGE_RSYNC_EXTRA_OPTS

Keyword added, thanks!