Libjpeg turbo automatically detects and compilies for altivec on powerpc, even without given use or other flags. This happens since version 1.5.0 and was not the case with version 1.4.2 (1.5.0 is the current unmasked version and 1.4.2 is not in portage anymore ) This resulted in all applications using it returning: illegal instruction on my G3: (750cx) libjpeg-turbo should not be the default if this is the case (and or) feature an altivec use flag patch for a correct setting. It should not install on systems lacking altivec. A workaround is to unmerge libjpeg-turbo and emerge media-libs/jpeg it should not be installed on ppc by default.
haschka@hirondelle ~ $ emerge --info Portage 2.2.28 (python 3.4.3-final-0, default/linux/powerpc/ppc32/13.0, gcc-4.9.3, glibc-2.22-r4, 4.1.15-gentoo-r1 ppc) ================================================================= System uname: Linux-4.1.15-gentoo-r1-ppc-750CX-with-gentoo-2.2 KiB Mem: 573976 total, 160932 free KiB Swap: 262140 total, 262140 free Timestamp of repository gentoo: Wed, 13 Jul 2016 07:30:01 +0000 sh bash 4.3_p42-r1 ld GNU ld (Gentoo 2.25.1 p1.1) 2.25.1 app-shells/bash: 4.3_p42-r1::gentoo dev-lang/perl: 5.20.2::gentoo dev-lang/python: 2.7.10-r1::gentoo, 3.4.3-r1::gentoo dev-util/cmake: 3.3.1-r1::gentoo dev-util/pkgconfig: 0.28-r2::gentoo sys-apps/baselayout: 2.2::gentoo sys-apps/openrc: 0.19.1::gentoo sys-apps/sandbox: 2.10-r1::gentoo sys-devel/autoconf: 2.13::gentoo, 2.69::gentoo sys-devel/automake: 1.9.6-r4::gentoo, 1.11.6-r1::gentoo, 1.14.1::gentoo, 1.15::gentoo sys-devel/binutils: 2.25.1-r1::gentoo sys-devel/gcc: 4.9.3::gentoo sys-devel/gcc-config: 1.7.3::gentoo sys-devel/libtool: 2.4.6::gentoo sys-devel/make: 4.1-r1::gentoo sys-kernel/linux-headers: 4.3::gentoo (virtual/os-headers) sys-libs/glibc: 2.22-r4::gentoo Repositories: gentoo location: /usr/portage sync-type: rsync sync-uri: rsync://rsync.gentoo.org/gentoo-portage priority: -1000 ACCEPT_KEYWORDS="ppc" ACCEPT_LICENSE="* -@EULA" CBUILD="powerpc-unknown-linux-gnu" CFLAGS="-Os -mcpu=750 -pipe" CHOST="powerpc-unknown-linux-gnu" CONFIG_PROTECT="/etc /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="-Os -mcpu=750 -pipe" DISTDIR="/usr/portage/distfiles" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-logs buildpkg config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned 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" LDFLAGS="-Wl,-O1 -Wl,--as-needed" 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="X acl alsa berkdb bzip2 cli cracklib crypt cxx dbus dri fontconfig fortran freetype gdbm gif iconv jpeg lcms modules ncurses nls nptl openmp pam pcre png ppc readline session ssl svg tcpd tiff truetype unicode xattr xft zlib" ABI_PPC="32" ALSA_CARDS="aoa aoa-fabric-layout aoa-onyx aoa-soundbus aoa-soundbus-i2s aoa-tas aoa-toonie powermac usb-audio via82xx" 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" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf supersta2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="keyboard mouse evdev" KERNL="linux" L10N="en de fr" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb21 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presentr-minimizer" LINGUAS="en de fr" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS"php5-5" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_4" UBY_TARGETS="ruby20 ruby21" USERLAND="GNU" VIDEO_CARDS="r128" XTABLES_ADDONS="qota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy conditin tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" Unset: CC, CPPFLAGS, CTARGET, CXX, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, AKEOPTS, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORAGE_RSYNC_EXTRA_OPTS, USE_PYTHON
There is further a --disable-simd feature in configure: so I suppose the solution would be to get something like this into the ebuild if [arch == ppc]
Sorry for the last comment it submitted by a typo: There is a --disable-simd option in ./configure .. I guess this bug could be resolved by adding an "altivec" useflag to the ebuild. If this flag is not set on the ppc platform the --disable-simd option shall be triggered. This then should allow for building libjpeg-turbo for G3 processors. This is also important as other packages i.e. firefox with external libjpeg need libjpeg-turbo.
Created attachment 442658 [details] ebuild with fix of the problem
If you feel you can still duplicate the problem feel free to reopen and update with present info.