g-ir-scanner contains a fixed "lib" for the pylibdir. Since current amd64 multilib has "lib64" for 64bit libdir and "lib" for 32bit libdir, this fixed libdir prevents multilib support. The origin of this issue can be found in the sources inside tools/g-ir-tool-template.in: It contains a fixed pylibdir = os.path.abspath(os.path.join(filedir, '..', 'lib', 'gobject-introspection')) Replacing the fixed "lib" with "@libdir@" inside src_prepare with e.g. sed -i "s/pylibdir = os.path.abspath(os.path.join(filedir, '..', 'lib', 'gobject-introspection'))/pylibdir = os.path.abspath(os.path.join(filedir, '..', '@libdir@', 'gobject-introspection'))/g" ./tools/g-ir-tool-template.in || die fixes this and adds multilib support to gobject-introspection. emerge --info: Portage 2.3.83-multilib (python 3.6.10-final-0, default/linux/amd64/17.1/hardened, gcc-9.2.0, glibc-2.31-r5, 4.19.124-gentoo x86_64) ================================================================= System uname: Linux-4.19.124-gentoo-x86_64-Intel-R-_Core-TM-_i7-4790_CPU_@_3.60GHz-with-gentoo-2.7 KiB Mem: 32856940 total, 4521468 free KiB Swap: 1048572 total, 1048060 free Head commit of repository gentoo: c7b427add9296779a8d2aeb06e7773e81ac6ef78 sh bash 5.0_p17 ld GNU ld (Gentoo 2.34 p4) 2.34.0 app-shells/bash: 5.0_p17::gentoo dev-java/java-config: 2.3.1::gentoo dev-lang/perl: 5.30.3-r1::gentoo dev-lang/python: 2.7.18::gentoo, 3.6.10-r2::gentoo, 3.7.7-r2::gentoo, 3.8.3::gentoo dev-util/cmake: 3.17.3::gentoo dev-util/pkgconfig: 0.29.2::gentoo sys-apps/baselayout: 2.7::gentoo sys-apps/openrc: 0.42.1::gentoo sys-apps/sandbox: 2.20::gentoo sys-devel/autoconf: 2.13-r1::gentoo, 2.69-r5::gentoo sys-devel/automake: 1.13.4-r2::gentoo, 1.15.1-r2::gentoo, 1.16.2::gentoo sys-devel/binutils: 2.33.1-r1::gentoo, 2.34-r1::gentoo sys-devel/gcc: 8.2.0-r6::gentoo, 9.2.0-r4::gentoo, 10.1.0-r1::gentoo sys-devel/gcc-config: 2.3::gentoo sys-devel/libtool: 2.4.6-r6::gentoo sys-devel/make: 4.3::gentoo sys-kernel/linux-headers: 5.7::gentoo (virtual/os-headers) sys-libs/glibc: 2.31-r5::gentoo Repositories: gentoo location: /usr/portage sync-type: git sync-uri: git+ssh://git@git.gentoo.org/repo/gentoo.git priority: -1000 eclass-overrides: gentoo local eclipse location: /var/lib/layman/eclipse masters: gentoo priority: 50 eclass-overrides: gentoo local enlightenment location: /var/lib/layman/enlightenment masters: gentoo priority: 50 eclass-overrides: gentoo local java location: /var/lib/layman/java masters: gentoo priority: 50 eclass-overrides: gentoo local multilib-portage location: /var/lib/layman/multilib-portage masters: gentoo priority: 50 eclass-overrides: gentoo local tastytea location: /var/lib/layman/tastytea masters: gentoo priority: 50 eclass-overrides: gentoo local local location: /usr/local/portage masters: gentoo priority: 100 eclass-overrides: gentoo local Installed sets: @fonts ACCEPT_KEYWORDS="amd64 ~amd64" ACCEPT_LICENSE="*" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=native -O2 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/lib64/libreoffice/program/sofficerc /usr/share/config /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo" CXXFLAGS="-march=native -O2 -pipe" DISTDIR="/usr/portage/distfiles" EMERGE_DEFAULT_OPTS="--keep-going" ENV_UNSET="DBUS_SESSION_BUS_ADDRESS DISPLAY GOBIN GOPATH PERL5LIB PERL5OPT PERLPREFIX PERL_CORE PERL_MB_OPT PERL_MM_OPT XAUTHORITY XDG_CACHE_HOME XDG_CONFIG_HOME XDG_DATA_HOME XDG_RUNTIME_DIR" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs collision-protect distlocks ebuild-locks fixlafiles force-multilib ipc-sandbox merge-sync metadata-transfer network-sandbox news parallel-fetch pid-sandbox preserve-libs protect-owned sandbox sfperms sign splitdebug strict strict-keepdir unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox xattr" FFLAGS="-O2 -pipe" GENTOO_MIRRORS="http://ftp.spline.inf.fu-berlin.de/mirrors/gentoo/ ftp://ftp.uni-erlangen.de/pub/mirrors/gentoo ftp://ftp.snt.utwente.nl/pub/os/linux/gentoo" LANG="de_DE.UTF8" LDFLAGS="-Wl,--as-needed -Wl,--hash-style=gnu" LINGUAS="en de" MAKEOPTS="-j6 --load-average=8" PKGDIR="/usr/portage/packages" PORTAGE_CONFIGROOT="/" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --exclude=/.git" PORTAGE_TMPDIR="/var/tmp" USE="3dnow X alsa amd64 crypt cups custom-cflags custom-cxxflags custom-optimization gpm hardened java5 java6 libtirpc mmx ncurses nls nptl nsplugin ogg openmp opus pam pie readline scanner seccomp split-usr sse sse2 ssl ssp system-sqlite unicode v4l vorbis vulkan xattr xinerama xtpax zlib" ADA_TARGET="gnat_2018" ALSA_CARDS="hda-intel" 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="karbon sheets words" 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 greis isync itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="libinput" KERNEL="linux" L10N="en-GB de" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" MULTILIB_ABI="amd64 x86" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php7-2" POSTGRES_TARGETS="postgres10 postgres11" PYTHON_SINGLE_TARGET="python3_6" PYTHON_TARGETS="python2_7 python3_6" RUBY_TARGETS="ruby26" SANE_BACKENDS="hp hp3500 hp3900 hp4200 hp5400 hp5590 hpljm1005 hpsj5s hs2p" 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" Unset: CC, CPPFLAGS, CTARGET, CXX, INSTALL_MASK, LC_ALL, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
gobject-introspection is not meant to have multilib support. That said, the hardcoded value doesn't feel strictly correct anyhow, as they are installed based on get_option('libdir'), so should be looked for based on that as well. This is something that should be brought upstream, but I can't deal with that time-wise right now - feel free to help in this regard. I don't want to really patch this without upstream acknowledging something about it.
