VBOX_GCC_TOOL is defined as GXX3. (Config.kmk line 1608) So TOOL_$(VBOX_GCC_TOOL)_CC is expanded to TOOL_GXX3_CC. (Config.kmk line 2823) However ebuild define TOOL_GCC3_CC, which is not used. Reproducible: Always Steps to Reproduce: 1.CC=clang CXX=clang++ 2.emerge app-emulation/virtualbox 3.Still using gcc and g++ Expected Results: @@ -261,11 +263,11 @@ MAKEOPTS="${MAKEJOBS} ${MAKELOAD}" MAKE="kmk" emake \ VBOX_BUILD_PUBLISHER=_Gentoo \ - TOOL_GCC3_CC="$(tc-getCC)" TOOL_GCC3_CXX="$(tc-getCXX)" \ - TOOL_GCC3_AS="$(tc-getCC)" TOOL_GCC3_AR="$(tc-getAR)" \ - TOOL_GCC3_LD="$(tc-getCXX)" TOOL_GCC3_LD_SYSMOD="$(tc-getLD)" \ - TOOL_GCC3_CFLAGS="${CFLAGS}" TOOL_GCC3_CXXFLAGS="${CXXFLAGS}" \ - VBOX_GCC_OPT="${CXXFLAGS}" \ + TOOL_GXX3_CC="$(tc-getCC)" TOOL_GXX3_CXX="$(tc-getCXX)" \ + TOOL_GXX3_AS="$(tc-getCC)" TOOL_GXX3_AR="$(tc-getAR)" \ + TOOL_GXX3_LD="$(tc-getCXX)" TOOL_GXX3_LD_SYSMOD="$(tc-getLD)" \ + TOOL_GXX3_CFLAGS="${CFLAGS}" TOOL_GXX3_CXXFLAGS="${CXXFLAGS}" \ + VBOX_GCC_OPT="${CXXFLAGS} -Wno-narrowing" \ TOOL_YASM_AS=yasm KBUILD_VERBOSE=2 \ VBOX_WITH_VBOXIMGMOUNT=1 \ all With this change I can build virtualbox using clang 10 emerge --info Portage 2.3.100 (python 3.7.7-final-0, default/linux/amd64/17.1, gcc-10.1.0, glibc-2.31-r3, 5.6.15-zen+ x86_64) ================================================================= System uname: Linux-5.6.15-zen+-x86_64-Intel-R-_Core-TM-_i5-6300HQ_CPU_@_2.30GHz-with-gentoo-2.7 KiB Mem: 16204600 total, 4671348 free KiB Swap: 25165812 total, 25165812 free Timestamp of repository gentoo: Sun, 31 May 2020 05:05:32 +0000 Head commit of repository gentoo: 29dfcbde3521121c8c0d046c97c9a2fd5a308189 Timestamp of repository gentoo-zh: Sat, 30 May 2020 21:05:04 +0000 Head commit of repository gentoo-zh: 9870b499055a28d08de14b10ce4c5cbbe035fd24 Timestamp of repository guru: Fri, 29 May 2020 17:35:06 +0000 Head commit of repository guru: a9d2e687e58efa0434e985fac6e77636ad0cec17 Timestamp of repository jorgicio: Sun, 31 May 2020 01:35:06 +0000 Head commit of repository jorgicio: a0312b73c4013b6e91c29ed39b3c5ba12c2036a8 Head commit of repository kwin-lowlatency-overlay: 6c9e44692ad18747978f800aea14e196bde0ee14 Timestamp of repository lanodanOverlay: Sun, 31 May 2020 00:35:05 +0000 Head commit of repository lanodanOverlay: 91212f78eba560ef5227e24182dd810b3735d328 Timestamp of repository lto-overlay: Sat, 30 May 2020 15:05:02 +0000 Head commit of repository lto-overlay: e47925a5f48b7db4787c9954c7f10a36eea79f61 Timestamp of repository mv: Sat, 30 May 2020 15:05:02 +0000 Head commit of repository mv: 7a29f3deb092b48a1a2ba0488e0d2fcd40a4929c Timestamp of repository tgbugs-overlay: Thu, 28 May 2020 12:05:25 +0000 Head commit of repository tgbugs-overlay: e916c66854949eb81d5a650cfb89b3faff8081a5 sh bash 5.0_p17 ld LLD 10.0.0 (compatible with GNU linkers) ccache version 3.7.9 [enabled] app-shells/bash: 5.0_p17::gentoo dev-java/java-config: 2.2.0-r4::gentoo dev-lang/perl: 5.30.2-r2::gentoo dev-lang/python: 2.7.18-r100::lto-overlay, 3.7.7-r3::lto-overlay dev-util/ccache: 3.7.9::gentoo dev-util/cmake: 3.17.3::gentoo sys-apps/baselayout: 2.7::gentoo sys-apps/openrc: 0.42.1::gentoo sys-apps/sandbox: 2.18::gentoo sys-devel/autoconf: 2.13-r1::gentoo, 2.69-r5::gentoo sys-devel/automake: 1.16.2::gentoo sys-devel/binutils: 2.34-r1::gentoo sys-devel/gcc: 9.3.0-r1::gentoo, 10.1.0::gentoo sys-devel/gcc-config: 2.3::gentoo sys-devel/libtool: 2.4.6-r6::gentoo sys-devel/make: 4.2.1-r4::gentoo sys-kernel/linux-headers: 5.6::gentoo (virtual/os-headers) sys-libs/glibc: 2.31-r3::gentoo Repositories: gentoo location: /usr/portage/gentoo sync-type: git sync-uri: https://github.com/gentoo-mirror/gentoo priority: -1000 12101111-overlay location: /usr/portage/local masters: gentoo gentoo-zh location: /usr/portage/gentoo-zh sync-type: git sync-uri: https://github.com/gentoo-mirror/gentoo-zh.git masters: gentoo guru location: /usr/portage/guru sync-type: git sync-uri: https://github.com/gentoo-mirror/guru.git masters: gentoo jorgicio location: /usr/portage/jorgicio sync-type: git sync-uri: https://github.com/gentoo-mirror/jorgicio.git masters: gentoo kwin-lowlatency-overlay location: /usr/portage/kwin-lowlatency-overlay sync-type: git sync-uri: https://github.com/agates/kwin-lowlatency-overlay.git masters: gentoo lanodanOverlay location: /usr/portage/lanodanOverlay sync-type: git sync-uri: https://github.com/gentoo-mirror/lanodanOverlay.git masters: gentoo lto-overlay location: /usr/portage/lto-overlay sync-type: git sync-uri: https://github.com/gentoo-mirror/lto-overlay.git masters: gentoo mv mv location: /usr/portage/mv sync-type: git sync-uri: https://github.com/gentoo-mirror/mv.git masters: gentoo tgbugs-overlay location: /usr/portage/tgbugs-overlay sync-type: git sync-uri: https://github.com/gentoo-mirror/tgbugs-overlay.git masters: gentoo Installed sets: @fcitx5 ACCEPT_KEYWORDS="amd64 ~amd64" ACCEPT_LICENSE="@FREE @BINARY-REDISTRIBUTABLE" CBUILD="x86_64-pc-linux-gnu" CC="clang" CFLAGS="-march=skylake -mtune=skylake -O3 -pipe -falign-functions=32 -fomit-frame-pointer -ffunction-sections -fdata-sections -flto=thin" 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" CXX="clang++" CXXFLAGS="-march=skylake -mtune=skylake -O3 -pipe -falign-functions=32 -fomit-frame-pointer -ffunction-sections -fdata-sections -flto=thin -stdlib=libc++" DISTDIR="/var/cache/distfiles" ENV_UNSET="DBUS_SESSION_BUS_ADDRESS DISPLAY GOBIN 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="-march=skylake -mtune=skylake -O3 -pipe -falign-functions=32 -fomit-frame-pointer -ffunction-sections -fdata-sections -flto=thin" FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs ccache 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="-march=skylake -mtune=skylake -O3 -pipe -falign-functions=32 -fomit-frame-pointer -ffunction-sections -fdata-sections -flto=thin" GENTOO_MIRRORS="https://mirrors.tuna.tsinghua.edu.cn/gentoo" LANG="zh_CN.UTF-8" LDFLAGS="-fuse-ld=lld -rtlib=compiler-rt -unwindlib=libunwind -flto=thin -Wl,-O3 -Wl,--gc-sections -march=skylake -mtune=skylake" MAKEOPTS="-j4" 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 acl alsa amd64 bzip2 clang cli compiler-rt crypt dbus default-compiler-rt default-libcxx dri elogind fortran gdbm gif iconv ipv6 jpeg libcxx libcxxabi libtirpc libunwind luajit multilib ncurses nls nptl opengl openmp pam pcre png policykit polkit pulseaudio readline seccomp split-usr ssl svg tcpd unicode vaapi vulkan wayland xattr zlib zsh-completion" ABI_X86="64" ADA_TARGET="gnat_2018" 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="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" INPUT_DEVICES="libinput" KERNEL="linux" L10N="zh-CN" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LLVM_TARGETS="X86 ARM AArch64 RISCV WebAssembly" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php7-4" POSTGRES_TARGETS="postgres10 postgres11" PYTHON_SINGLE_TARGET="python3_7" PYTHON_TARGETS="python3_7" QEMU_SOFTMMU_TARGETS="arm aarch64 i386 x86_64 riscv32 riscv64" QEMU_USER_TARGETS="arm aarch64" RUBY_TARGETS="ruby27" 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: CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, LINGUAS, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
This is fixed in virtualbox-6.1.10
