Well the only difference between the output of `emerge -pv x11-libs/cairo` on your machine vs. mine is that you appear to be building 64 and 32 bit:
mine: `ABI_X86="64 -32 -x32"` yours: `ABI_X86="64 32 -x32"` As for the global setting for `threads`, I have it enabled, but isn't that a good thing? Should I disable threads globally? I removed it from make.conf and cairo still won't build, but that's unsurprising, since the build makes no mention of that USE flag. # emerge --info | grep threads USE="X a52 aac acl acpi aes alsa amd64 avx avx2 berkdb bluetooth branding bzip2 cairo cdda cdr cli colord cracklib crypt cxx dbus dri dts dvd dvdr eds emboss encode evo exif fam firefox flac fma3 fortran fuse gdbm gif glamor gnome gnome-keyring gnome-online-accounts gpm gstreamer gtk iconv introspection ipv6 jpeg lcms libnotify libsecret mad matroska mmx mmxext mng modules mp3 mp4 mpeg mtp multilib nautilus ncurses networkmanager nls nptl offensive ogg ogm opengl openmp pam pango pcre pdf png policykit popcnt ppds pulseaudio qt3support readline sdl seccomp session spell sqlite sse sse2 sse3 sse4_1 sse4_2 ssl ssse3 startup-notification svg systemd tcpd theora threads tiff truetype udev udisks unicode upower usb v4l vaapi vdpau vim-syntax vorbis vpx x264 x265 xattr xcb xml xpm xv xvid xvmc zlib" ABI_X86="64" 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" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx avx2 fma3 mmx mmxext popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="libinput" KERNEL="linux" L10N="en-GB en" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="en_GB en" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-6" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_4" RUBY_TARGETS="ruby20 ruby21" USERLAND="GNU" VIDEO_CARDS="nvidia" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"
