I was cross-compiling udev-216 when this error showed up. checking for sys/capability.h... no configure: error: *** POSIX caps headers not found I got it compiling by installing sys-libs/libcap.
emerge-armv7a-hardfloat-linux-gnueabi --info Portage 2.2.18 (python 2.7.9-final-0, default/linux/arm/13.0/armv7a, gcc-4.8.4, glibc-2.20-r2, 3.18.11-gentoo x86_64) ================================================================= System uname: Linux-3.18.11-gentoo-x86_64-Intel-R-_Core-TM-_i7-4500U_CPU_@_1.80GHz-with-gentoo-2.2 KiB Mem: 8077148 total, 982756 free KiB Swap: 0 total, 0 free Timestamp of repository gentoo: Wed, 10 Jun 2015 10:30:01 +0000 sh bash 4.3_p33-r2 ld GNU ld (Gentoo 2.24 p1.4) 2.24 app-shells/bash: 4.3_p33-r2::gentoo dev-lang/python: 2.7.9-r1::gentoo, 3.3.5-r1::gentoo sys-apps/baselayout: 2.2::gentoo sys-apps/openrc: 0.13.11::gentoo sys-apps/sandbox: 2.6-r1::gentoo sys-devel/binutils: 2.24-r3::gentoo sys-devel/gcc: 4.8.4::gentoo sys-devel/gcc-config: 1.7.3::gentoo sys-devel/make: 4.1-r1::gentoo sys-kernel/linux-headers: 3.18::gentoo (virtual/os-headers) sys-libs/glibc: 2.20-r2::gentoo Repositories: gentoo location: /usr/portage sync-type: rsync sync-uri: rsync://rsync.gentoo.org/gentoo-portage priority: -1000 ACCEPT_KEYWORDS="arm" ACCEPT_LICENSE="* -@EULA" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-O2 -pipe -fomit-frame-pointer" CHOST="armv7a-hardfloat-linux-gnueabi" CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/gconf /etc/gentoo-release /etc/sandbox.d /etc/terminfo" CXXFLAGS="-O2 -pipe -fomit-frame-pointer" DISTDIR="/usr/portage/distfiles" FCFLAGS="-O2 -pipe -march=armv7-a" FEATURES="assume-digests binpkg-logs buildpkg config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news nodoc noinfo noman parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync" FFLAGS="-O2 -pipe -march=armv7-a" GENTOO_MIRRORS="http://distfiles.gentoo.org" LDFLAGS="-Wl,-O1 -Wl,--as-needed" PKGDIR="/usr/armv7a-hardfloat-linux-gnueabi/packages/" PORTAGE_CONFIGROOT="/usr/armv7a-hardfloat-linux-gnueabi/" 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" PORTAGE_TMPDIR="/usr/armv7a-hardfloat-linux-gnueabi/tmp/" USE="arm armv5te armv6 armv6t2 berkdb bzip2 cli cracklib crypt cxx dri fortran gdbm iconv ipv6 modules ncurses nls nptl openmp pcre readline session ssl tcpd unicode zlib" 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 mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-5" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_3" RUBY_TARGETS="ruby19 ruby20" USERLAND="GNU" VIDEO_CARDS="exynos fbdev omap omapfb dummy v4l" 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, LANG, LC_ALL, MAKEOPTS, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS, USE_PYTHON
The real problem is that it's doing this even when USE=-cap. I'm guessing it was introduced in the transition to Meson. I have reproduced this natively so it's nothing to do with cross-compiling.
Mordern versions of sys-fs/udev correctly depend on sys-libs/libcap unconditionally.
