emerge --info app-text/docbook-xsl-ns-stylesheets

gistfile1.txt

Portage 2.3.11 (python 3.4.6-final-0, hardened/linux/amd64/no-multilib, gcc-6.4.0, glibc-2.25-r7, 4.13.6 x86_64)
=================================================================
                         System Settings
=================================================================
System uname: Linux-4.13.6-x86_64-Intel-R-_Core-TM-_i5-4300U_CPU_@_1.90GHz-with-gentoo-2.4.1
KiB Mem:     8097884 total,    253012 free
KiB Swap:    8373568 total,   8373568 free
Timestamp of repository gentoo: Thu, 12 Oct 2017 18:44:07 +0000
Head commit of repository gentoo: ba778bb90a6553cd6b002976b44989ae284c1524

sh bash 4.4_p12
ld GNU ld (Gentoo 2.29.1 p1.0) 2.29.1
app-shells/bash:          4.4_p12::gentoo
dev-lang/perl:            5.26.1::gentoo
dev-lang/python:          2.7.14::gentoo, 3.4.6::gentoo
dev-util/cmake:           3.9.4::gentoo
dev-util/pkgconfig:       0.29.2::gentoo
sys-apps/baselayout:      2.4.1-r2::gentoo
sys-apps/openrc:          0.32.1::gentoo
sys-apps/sandbox:         2.12::gentoo
sys-devel/autoconf:       2.13::gentoo, 2.69-r4::gentoo
sys-devel/automake:       1.15.1-r1::gentoo
sys-devel/binutils:       2.29.1::gentoo
sys-devel/gcc:            6.4.0::gentoo
sys-devel/gcc-config:     1.9.0::gentoo
sys-devel/libtool:        2.4.6-r4::gentoo
sys-devel/make:           4.2.1-r1::gentoo
sys-kernel/linux-headers: 4.13::gentoo (virtual/os-headers)
sys-libs/glibc:           2.25-r7::gentoo
Repositories:

gentoo
    location: /var/portage/tree
    sync-type: git
    sync-uri: https://github.com/gentoo-mirror/gentoo.git
    sync-user: portage
    priority: -1000
    sync-git-clone-extra-opts: --branch master

g-cpan
    location: /var/portage/g-cpan-overlay
    masters: gentoo
    priority: 0

local
    location: /var/portage/overlay
    masters: gentoo
    priority: 1

holgersson-overlay
    location: /var/layman/holgersson-overlay
    sync-type: laymansync
    sync-uri: https://git.holgersson.xyz/holgersson-overlay
    sync-user: portage
    masters: gentoo
    priority: 50

imaging
    location: /var/layman/imaging
    sync-type: laymansync
    sync-uri: https://github.com/gerddie/gentoo-imaging.git
    masters: gentoo
    priority: 50

Installed sets: @SDR, @custom_KDE, @electronics, @games
ACCEPT_KEYWORDS="amd64 ~amd64"
ACCEPT_LICENSE="* -@EULA"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-O2 -pipe -march=native"
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 /etc/texmf/language.dat.d /etc/texmf/language.def.d /etc/texmf/updmap.d /etc/texmf/web2c"
CXXFLAGS="-O2 -pipe -march=native"
DISTDIR="/var/portage/distfiles"
EMERGE_DEFAULT_OPTS="--quiet-build --autounmask=n --binpkg-respect-use=y"
FCFLAGS="-O2 -pipe"
FEATURES="assume-digests binpkg-logs buildpkg cgroup config-protect-if-modified distlocks ebuild-locks fixlafiles ipc-sandbox merge-sync multilib-strict network-sandbox news nodoc noinfo parallel-fetch preserve-libs protect-owned sandbox sfperms sign strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"
FFLAGS="-O2 -pipe"
GENTOO_MIRRORS="http://ftp.halifax.rwth-aachen.de/gentoo/"
LANG="de_DE.utf8"
LDFLAGS="-Wl,-O1 -Wl,--as-needed"
MAKEOPTS="-j5 -l5"
PKGDIR="/var/portage/packages"
PORTAGE_COMPRESS="xz"
PORTAGE_COMPRESS_FLAGS="-6 -T4"
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 acl acpi alsa amd64 bash-completion berkdb bluetooth branding bzip2 caps cgroups cli colord cracklib crypt cryptsetup cups cxx dbus djvu dri egl elogind exif fam firefox flac fontconfig git glamor gles gpg gpm graphicsmagick gstreamer hardened hunspell iconv icu int64 ipv6 jpeg justify kipi lapack ldap libinput libnotify lzma modules ncurses networkmanager nftables nls nptl offensive ogg opengl openmp openmpi openmpi2 opus pam pax_kernel pcre pdf phonon pic pie pkcs11 plasma png policykit postscript pulseaudio qml qt5 readline samba sasl sdl seccomp semantic-desktop session smp sound spell ssh ssl ssp startup-notification svg tcpd theora threads tiff truetype udev udisks unicode upower urandom usb v4l vaapi video vim-syntax vorbis vpx wavpack wayland x264 x265 xattr xcb xcomposite xkb xtpax xv xvid zlib zsh-completion" ABI_X86="64" 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="kexi words flow plan sheets stage tables krita karbon braindump author" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx avx2 f16c fma3 mmx mmxext popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock isync itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="evdev synaptics wacom" KERNEL="linux" L10N="de de_DE ru ru_RU" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="de de_DE ru ru_RU" LLVM_TARGETS="BPF X86" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-6" POSTGRES_TARGETS="postgres9_5" PYTHON_SINGLE_TARGET="python3_4" PYTHON_TARGETS="python2_7 python3_4" RUBY_TARGETS="ruby24" USERLAND="GNU" VIDEO_CARDS="intel i965" 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_BUNZIP2_COMMAND, PORTAGE_RSYNC_EXTRA_OPTS

=================================================================
                        Package Settings
=================================================================

app-text/docbook-xsl-ns-stylesheets-1.78.0::gentoo was built with the following:
USE="-ruby"

When I pushed the change it worked, but last night my system disk crashed, so that I can't check which version of docbook-xsl was installed. On Debian it builds successfully against docbook-xsl-ns-1.79.