After upgrading my KDE4 system to kde-apps/kmix-16.04.3-r1, the OSD stopped working. I found out this can be solved by removing KMIX_KF5_BUILD from mycmakeargs variable in the ebuild and recompiling kmix. I think this should be somehow detected automatically, depending on whether KDE4 or KDE Plasma is being used.
# emerge --info Portage 2.2.28 (python 3.4.3-final-0, default/linux/amd64/13.0/desktop, gcc-4.9.3, glibc-2.22-r4, 4.7.0 x86_64) ================================================================= System uname: Linux-4.7.0-x86_64-Intel-R-_Core-TM-_i7-4600U_CPU_@_2.10GHz-with-gentoo-2.2 KiB Mem: 8070472 total, 2269188 free KiB Swap: 8388604 total, 8383428 free Timestamp of repository gentoo: Tue, 23 Aug 2016 07:45:01 +0000 sh bash 4.3_p42-r1 ld GNU ld (Gentoo 2.25.1 p1.1) 2.25.1 distcc 3.2rc1 x86_64-pc-linux-gnu [disabled] app-shells/bash: 4.3_p42-r1::gentoo dev-java/java-config: 2.2.0-r3::gentoo dev-lang/perl: 5.20.2::gentoo dev-lang/python: 2.7.10-r1::gentoo, 3.4.3-r1::gentoo dev-util/cmake: 3.5.2-r1::gentoo dev-util/pkgconfig: 0.28-r2::gentoo sys-apps/baselayout: 2.2::gentoo sys-apps/openrc: 0.21.3::gentoo sys-apps/sandbox: 2.10-r1::gentoo sys-devel/autoconf: 2.13::gentoo, 2.69::gentoo sys-devel/automake: 1.11.6-r1::gentoo, 1.13.4::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.cz.gentoo.org/gentoo-portage priority: -1000 Local-overlay location: /usr/local/portage masters: gentoo priority: 0 Oskar-overlay location: /var/lib/layman/oskaroverlay masters: gentoo priority: 1 ACCEPT_KEYWORDS="amd64" ACCEPT_LICENSE="*" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-O2 -pipe -march=core-avx2" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/config /usr/share/gnupg/qualified.txt /usr/share/themes/oxygen-gtk/gtk-2.0" 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=core-avx2" DISTDIR="/usr/portage/distfiles" FCFLAGS="-O2 -pipe" FEATURES="assume-digests binpkg-logs candy config-protect-if-modified distlocks ebuild-locks fakeroot 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://ftp.fi.muni.cz/pub/linux/gentoo/" LANG="cs_CZ.UTF-8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" MAKEOPTS="-j5 -l15" 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 a52 aac acl acpi alsa amd64 avx avx256 berkdb bluetooth branding bzip2 cairo cdda cdr cgmanager cli consolekit cracklib crypt cups cxx dane dbus dri drm dts dvb dvd dvdr emboss encode exif fam ffmpeg firefox flac fontconfig fortran freerdp gbm gdbm gif glamor gpm gtk iconv icu idn iproute2 ipv6 jpeg kde lcms ldap ldns libnotify lzma mad mmx mmxext mng modules mp3 mp4 mpeg multilib ncurses nls nptl offensive ogg opengl openmp pam pango passwordsave pcre pdf png policykit ppds pulseaudio python qt3support qt4 readline scanner sdl seccomp session sndfile speex spell sse sse2 sse3 sse4 sse4_1 ssl ssse3 startup-notification svg tcpd tiff truetype udev udisks unicode upower usb uxa v4l vaapi vorbis wxwidgets x264 xattr xcb xinerama xml xv xvid xvmc xz yuv4mpeg zlib" ABI_X86="64" ALSA_CARDS="hda-intel usb-audio" 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" GRUB_PLATFORMS="efi-64 pc qemu" INPUT_DEVICES="evdev synaptics" KERNEL="linux" L10N="cs en-US en" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LINGUAS="cs en" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-6" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_4" RUBY_TARGETS="ruby20 ruby21" SANE_BACKENDS="pixma epson epson2" USERLAND="GNU" VIDEO_CARDS="intel" 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, LC_ALL, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON
kmix is most likely not going to be dialled back to kdelibs4. I'd consider the missing OSD an inconvenience, but a minor one.
Sorry, but Plasma 4 has been completely unsupported now for a year and will be removed in the near future so we won't be doing any more work on it. I can't think of any clean way to implement such automatic detection anyway. You could consider looking at the kde-sunset overlay where kmix-4.14.3 now lives.
