i only checked the latest version, not sure if older ones fail as well audacious uses CFLAGS when compiling C++ objects instead of CXXFLAGS ... here's one such snippet: CXX adplug-xmms.cc cc1plus: warning: command line option "-Wimplicit-function-declaration" is valid for C/ObjC but not for C++ and as you can see: $ portageq envvar -v CFLAGS CXXFLAGS CFLAGS='-O2 -march=k8 -pipe -Wimplicit-function-declaration' CXXFLAGS='-O2 -march=k8 -pipe' Portage 2.1_rc4-r3 (default-linux/amd64/2006.0, gcc-4.1.1, glibc-2.4-r3, 2.6.16.9-grsec x86_64) ================================================================= System uname: 2.6.16.9-grsec x86_64 AMD Athlon(tm) 64 Processor 3500+ Gentoo Base System version 1.6.15 distcc 2.18.3 x86_64-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled] ccache version 2.4 [enabled] dev-lang/python: 2.4.3-r1 dev-python/pycrypto: 2.0.1-r5 dev-util/ccache: 2.4-r1 dev-util/confcache: [Not Present] sys-apps/sandbox: 1.2.18.1 sys-devel/autoconf: 2.13, 2.59-r7 sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2 sys-devel/binutils: 2.15.92.0.2-r10, 2.16-r1, 2.16.1, 2.16.1-r2, 2.16.90.0.3, 2.16.91.0.1, 2.16.91.0.2, 2.16.91.0.3, 2.16.91.0.4, 2.16.91.0.5, 2.16.91.0.6, 2.16.91.0.7, 2.16.92, 2.16.93 sys-devel/gcc-config: 1.3.13-r2 sys-devel/libtool: 1.5.22 virtual/os-headers: 2.6.11-r6 ACCEPT_KEYWORDS="amd64 ~amd64" AUTOCLEAN="yes" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-O2 -march=k8 -pipe -Wimplicit-function-declaration" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config /var/qmail/alias /var/qmail/control /var/vpopmail/domains /var/vpopmail/etc" CONFIG_PROTECT_MASK="/etc/gconf /etc/revdep-rebuild /etc/terminfo /etc/texmf/web2c /etc/env.d" CXXFLAGS="-O2 -march=k8 -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="assume-digests autoconfig ccache cvs distlocks metadata-transfer noinfo sandbox sfperms sign splitdebug" GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo" INSTALL_MASK="/usr/share/applications /usr/kde/*/share/applications /lib/udev/devices" LANG="en" LC_ALL="en_US" LDFLAGS="-Wl,-O1 -Wl,-z,relro" LINGUAS="de en es cs" MAKEOPTS="-j6" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude='/distfiles' --exclude='/local' --exclude='/packages'" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" SYNC="rsync://gentoo/gentoo-portage" USE="amd64 X a52 aac aalib acl adns aio alsa asf audiofile berkdb bitmap-fonts bzip2 cairo cddb cdparanoia cli crypt cups curl dba directfb divx4linux dri dts dvd dvdr dvdread emboss encode exif fbcon ffmpeg flac flash foomaticdb ftp gd gif glitz glut gphoto2 gpm gtk gtk2 imap imlib ipv6 isdnlog jbig joystick jpeg jpeg2k libcaca libedit lzo lzw lzw-tiff mad maildir matroska mikmod mime mng modplug mp3 mpeg mplayer multislot ncurses nls nptl nptlonly nvidia offensive ogg oggvorbis openal opengl pcre pdflib perl pic png pppd python quicktime readline reflection samba sdl session sndfile spell spl ssl subtitles svg tcltk tcpd tga theora threads tiff truetype truetype-fonts type1-fonts usb vcd vorbis wmf xanim xine xinerama xml xml2 xmms xorg xpm xrandr xv xvid xvmc zlib elibc_glibc kernel_linux linguas_de linguas_en linguas_es linguas_cs userland_GNU video_cards_nvidia" Unset: CTARGET, EMERGE_DEFAULT_OPTS, PORTAGE_RSYNC_EXTRA_OPTS
Fixed in SVN, thanks. (please mark as RESO UPSTREAM).
This will be in the next release.