app-office/libreoffice-6.4.4.2 build fails

[evilbulgarian]

❯ emerge --info
Portage 2.3.99 (python 3.7.7-final-0, default/linux/amd64/17.1/desktop/plasma/systemd, gcc-10.1.0, glibc-2.30-r8, 5.6.14+ x86_64)

System uname: Linux-5.6.14+-x86_64-Intel-R-_Core-TM-i7-8550U_CPU@_1.80GHz-with-gentoo-2.6
KiB Mem: 16361108 total, 10754616 free
KiB Swap: 16382972 total, 16382972 free
Timestamp of repository gentoo: Sun, 07 Jun 2020 23:35:42 +0000
Head commit of repository gentoo: cdbfc31aa7387affe8cb253454fb9de8fbbd8939

Head commit of repository lto-overlay: 4b014e4

Head commit of repository mv: 63a85b423c57b520b5817df2137d68387bd2109d

Head commit of repository steam-overlay: ae3e928b83b722ae6197fc1bc78859b592b819e5

Head commit of repository tlp: ced908095a1bafc1af3583efc4a24b39e2ab8c12

Head commit of repository eroen: 168c481db277e12e30ba6dea71a774337512ce32

Head commit of repository throttled: aea89b0942bf30837e19766ef93206096a4d0c4f

sh bash 5.0_p17
ld GNU ld (Gentoo 2.33.1 p2) 2.33.1
distcc 3.3.3 x86_64-pc-linux-gnu [disabled]
ccache version 3.7.9 [disabled]
app-shells/bash: 5.0_p17::gentoo
dev-java/java-config: 2.2.0-r4::gentoo
dev-lang/perl: 5.30.3::gentoo
dev-lang/python: 2.7.18::gentoo, 3.6.10-r2::gentoo, 3.7.7-r2::gentoo, 3.8.2-r2::gentoo
dev-util/ccache: 3.7.9::gentoo
dev-util/cmake: 3.16.5::gentoo
dev-util/pkgconfig: 0.29.2::gentoo
sys-apps/baselayout: 2.6-r1::gentoo
sys-apps/sandbox: 2.18::gentoo
sys-devel/autoconf: 2.13-r1::gentoo, 2.69-r4::gentoo
sys-devel/automake: 1.16.1-r1::gentoo
sys-devel/binutils: 2.33.1-r1::gentoo
sys-devel/gcc: 10.1.0::gentoo
sys-devel/gcc-config: 2.2.1::gentoo
sys-devel/libtool: 2.4.6-r6::gentoo
sys-devel/make: 4.2.1-r4::gentoo
sys-kernel/linux-headers: 5.4-r1::gentoo (virtual/os-headers)
sys-libs/glibc: 2.30-r8::gentoo
Repositories:

gentoo
location: /usr/portage
sync-type: git
sync-uri: https://anongit.gentoo.org/git/repo/sync/gentoo.git
priority: -1000

local-grendel
location: /usr/local/portage
masters: gentoo

x-portage
location: /usr/local/portage
masters: gentoo
priority: 0

lto-overlay
location: /var/lib/layman/lto-overlay
sync-type: git
sync-uri: https://github.com/InBetweenNames/gentooLTO.git
masters: gentoo mv
priority: 50

mv
location: /var/lib/layman/mv
sync-type: git
sync-uri: https://anongit.gentoo.org/git/user/mv.git
masters: gentoo
priority: 50

steam-overlay
location: /var/lib/layman/steam
sync-type: git
sync-uri: https://github.com/anyc/steam-overlay.git
masters: gentoo
priority: 50

tlp
location: /var/lib/layman/tlp
sync-type: git
sync-uri: git://github.com/dywisor/tlp-portage.git
masters: gentoo
priority: 50

eroen
location: /usr/local/portage/eroen
sync-type: git
sync-uri: https://anongit.gentoo.org/git/user/eroen.git
masters: gentoo
priority: 9999

throttled
location: /usr/local/portage/throttled
sync-type: git
sync-uri: https://github.com/erpalma/throttled-overlay.git
masters: gentoo
priority: 9999

Installed sets: @steam
ACCEPT_KEYWORDS="amd64"
ACCEPT_LICENSE="*"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-march=skylake -mabm -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=8 -fuse-linker-plugin -pipe -falign-functions=32"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/share/config /usr/share/easy-rsa /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=skylake -mabm -O3 -fgraphite-identity -floop-nest-optimize -fdevirtualize-at-ltrans -fipa-pta -fno-semantic-interposition -flto=8 -fuse-linker-plugin -pipe -falign-functions=32"
DISTDIR="/usr/portage/distfiles"
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 config-protect-if-modified distlocks ebuild-locks fixlafiles ipc-sandbox merge-sync multilib-strict network-sandbox news parallel-fetch pid-sandbox preserve-libs protect-owned qa-unresolved-soname-deps sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"
FFLAGS="-O2 -pipe"
GENTOO_MIRRORS="http://distfiles.gentoo.org"
LANG="en_US.utf8"
LC_ALL="en_US.utf8"
LDFLAGS="-Wl,-O1 -Wl,--as-needed -Wl,--hash-style=gnu"
LINGUAS="en bg"
MAKEOPTS="-j8 -l5"
PKGDIR="/var/cache/binpkgs"
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="X a52 aac aalib acpi adns alsa amd64 apng archive aspell async autoipd autoreplace avahi bash-completion bluetooth branding btrfs bzip2 cairo caps cdda cdinstall cdr cli client-libs crypt cryptsetup cups curl custom-cflags custom-optimization dbus declarative dhcp dolphin dri dri3 dts dvd dvdr egl encode epub exif ffmpeg flac fuse gallium gd gdbm geoclue geoip gif gles gnome-keyring gnutls gphoto2 graphite gstreamer haptic hardcoded-tables hddtemp hwaccel i3 ibmacpi iconv icu imagemagick imap imlib introspection iproute2 ipv6 ithreads iwd javascript jpeg jumbo-build kde kdenlive kipi kwallet lame laptop lcms libaom libcaca libinput libkms libnotify libtirpc lm_sensors logrotate lto lzma lzo mad matroska minizip mng mobi mp3 mp4 mpeg mtp multilib musicbrainz mysql ncurses network networkmanager nonfsv4 nptl offensive ogg opengl openmp optimized-qmake pam pango pch pcre pdf pgo phonon pic pie plasma png pnp policykit postproc ppds pulseaudio qml qt5 rar readline rpc rss rtmp s3tc samba sasl sdl seccomp semantic-desktop smi smime smtp speex spell split-usr sqlite srt ssl ssse3 svg swaybar swaybg swaygrab swaylock swaymsg system-cairo system-ffmpeg system-icu system-jpeg system-libevent system-libvpx system-llvm system-sqlite systemd theora threads tidy tiff tordns truetype udev udisks udisks2 ulaw unicode upower urandom usb user-session userlocales vaapi vim vim-syntax vnc vorbis vpx wayland webp widgets wifi x264 xattr xcb xml xv xvid zeroconf zip zlib zsh-completion" ABI_X86="64" ADA_TARGET="gnat_2018" 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="karbon sheets words" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx avx2 f16c fma3 mmx mmxext pclmul 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" GRUB_PLATFORMS="pc efi-64" INPUT_DEVICES="libinput" KERNEL="linux" L10N="en bg" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php7-2" POSTGRES_TARGETS="postgres10 postgres11" PYTHON_SINGLE_TARGET="python3_7" PYTHON_TARGETS="python2_7 python3_7" RUBY_TARGETS="ruby24 ruby25" USERLAND="GNU" VIDEO_CARDS="intel i965 iris" 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, EMERGE_DEFAULT_OPTS, INSTALL_MASK, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS

libreoffice.log

[thubble]

You need to filter out -fno-semantic-interposition. There's been a PR open for this for a while but it hasn't been merged yet: #478

Filtering out only this flag allows libreoffice to build for me.