https://github.com/msgpack/msgpack-c/blob/c-6.0.0/CMakeLists.txt#L29
Sorry, accidentally pressed enter before I finished filling out the description. --- This is incorrect on amd64 where the real libdir is /usr/lib64, which causes link-time failures when using lld (since GNU ld skips incompatible libraries by default). --- Portage 3.0.61 (python 3.11.7-final-0, default/linux/amd64/17.1, gcc-13, glibc-2.38-r10, 6.1.67-gentoo-dist x86_64) ================================================================= System uname: Linux-6.1.67-gentoo-dist-x86_64-AMD_Ryzen_7_5800H_with_Radeon_Graphics-with-glibc2.38 KiB Mem: 20474744 total, 15512348 free KiB Swap: 0 total, 0 free Timestamp of repository gentoo: Tue, 13 Feb 2024 19:15:01 +0000 Head commit of repository gentoo: 407e80adcddabb2c8c74c9ce9e05343d1c4f44e1 sh bash 5.1_p16-r6 ld GNU ld (Gentoo 2.40 p7) 2.40.0 app-misc/pax-utils: 1.3.7::gentoo app-shells/bash: 5.1_p16-r6::gentoo dev-build/autoconf: 2.71-r6::gentoo dev-build/automake: 1.16.5-r2::gentoo dev-build/cmake: 3.27.9::gentoo dev-build/libtool: 2.4.7-r1::gentoo dev-build/make: 4.4.1-r1::gentoo dev-build/meson: 1.3.0-r2::gentoo dev-lang/perl: 5.38.2-r1::gentoo dev-lang/python: 3.11.7::gentoo, 3.12.1_p1::gentoo dev-lang/rust-bin: 1.74.1::gentoo sys-apps/baselayout: 2.14-r2::gentoo sys-apps/openrc: 0.53::gentoo sys-apps/sandbox: 2.38::gentoo sys-devel/binutils: 2.40-r9::gentoo, 2.41-r3::gentoo sys-devel/binutils-config: 5.5::gentoo sys-devel/clang: 17.0.6::gentoo sys-devel/gcc: 13.2.1_p20240113-r1::gentoo sys-devel/gcc-config: 2.11::gentoo sys-devel/lld: 17.0.6::gentoo sys-devel/llvm: 17.0.6::gentoo sys-kernel/linux-headers: 6.6::gentoo (virtual/os-headers) sys-libs/glibc: 2.38-r10::gentoo Repositories: gentoo location: /var/db/repos/gentoo sync-type: rsync sync-uri: rsync://rsync.gentoo.org/gentoo-portage priority: -1000 volatile: False sync-rsync-verify-metamanifest: yes sync-rsync-extra-opts: sync-rsync-verify-jobs: 1 sync-rsync-verify-max-age: 24 Binary Repositories: gentoobinhost priority: 1 sync-uri: https://gentoo.osuosl.org/releases/amd64/binpackages/17.1/x86-64 ACCEPT_KEYWORDS="amd64" ACCEPT_LICENSE="@FREE" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=native -Os -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo" CXXFLAGS="-march=native -Os -pipe" DISTDIR="/var/cache/distfiles" ENV_UNSET="CARGO_HOME DBUS_SESSION_BUS_ADDRESS DISPLAY GDK_PIXBUF_MODULE_FILE GOBIN GOPATH PERL5LIB PERL5OPT PERLPREFIX PERL_CORE PERL_MB_OPT PERL_MM_OPT XAUTHORITY XDG_CACHE_HOME XDG_CONFIG_HOME XDG_DATA_HOME XDG_RUNTIME_DIR XDG_STATE_HOME" FCFLAGS="-march=native -Os -pipe" FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs binpkg-multi-instance buildpkg-live config-protect-if-modified distlocks ebuild-locks fixlafiles ipc-sandbox merge-sync multilib-strict network-sandbox news parallel-fetch pid-sandbox pkgdir-index-trusted 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=native -Os -pipe" GENTOO_MIRRORS="http://distfiles.gentoo.org" LANG="en_GB.utf8" LDFLAGS="-Wl,-O1 -Wl,--as-needed" LEX="flex" MAKEOPTS="-j8 -l8" 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" SHELL="/bin/zsh" USE="acl amd64 bzip2 cli crypt dri fortran gdbm iconv ipv6 libtirpc multilib ncurses nls openmp pam pcre readline seccomp split-usr ssl test-rust unicode xattr zlib" ABI_X86="64" ADA_TARGET="gnat_2021" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_anon authn_dbm authn_file authz_dbm authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir env expires ext_filter file_cache filter headers include info log_config logio 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="mmx mmxext sse sse2 aes avx avx2 f16c fma3 pclmul popcnt rdrand sha sse3 sse4_1 sse4_2 sse4a ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock greis isync itrax mtk3301 ntrip navcom oceanserver oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 tsip tripmate tnt ublox" GRUB_PLATFORMS="pc" INPUT_DEVICES="libinput" KERNEL="linux" LCD_DEVICES="bayrad cfontz glk hd44780 lb216 lcdm001 mtxorb text" LUA_SINGLE_TARGET="lua5-1" LUA_TARGETS="lua5-1" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php8-1" POSTGRES_TARGETS="postgres15" PYTHON_SINGLE_TARGET="python3_11" PYTHON_TARGETS="python3_11" RUBY_TARGETS="ruby31" VIDEO_CARDS="amdgpu fbdev intel nouveau radeon radeonsi vesa dummy" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipp2p iface geoip fuzzy condition tarpit sysrq proto logmark ipmark dhcpmac delude chaos account" Unset: ADDR2LINE, AR, ARFLAGS, AS, ASFLAGS, CC, CCLD, CONFIG_SHELL, CPP, CPPFLAGS, CTARGET, CXX, CXXFILT, ELFEDIT, EMERGE_DEFAULT_OPTS, EXTRA_ECONF, F77FLAGS, FC, GCOV, GPROF, INSTALL_MASK, LC_ALL, LD, LFLAGS, LIBTOOL, LINGUAS, MAKE, MAKEFLAGS, NM, OBJCOPY, OBJDUMP, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, PYTHONPATH, RANLIB, READELF, RUSTFLAGS, SIZE, STRINGS, STRIP, YACC, YFLAGS
This should really be handled via upstream moving to CMAKE_INSTALL_LIBDIR here. Worth opening an upstream bug report too.