e.g.: https://luci-milo.appspot.com/buildbot/chromiumos.tryserver/pre_cq/41024

metrics-0.0.1-r2183: FAILED: metrics_daemon 
metrics-0.0.1-r2183: flock linker.lock x86_64-pc-linux-gnu-clang++ -Wl,-O2 -Wl,--as-needed -Wl,-O2 -Wl,--as-needed -Wl,-z,relro -Wl,-z,noexecstack -Wl,-z,now -Wl,--as-needed -pie -pthread -Wl,-rpath=\$ORIGIN/lib/ -Wl,-rpath-link=lib/ -o metrics_daemon -Wl,--start-group obj/metrics/libmetrics_daemon.a obj/metrics/libmetrics_proto.a obj/metrics/libupload_service.a lib/libmetrics-395517.so -Wl,--end-group -lrootdev -lvboot_host -ldbus-1 -lbrillo-395517 -lbase-395517 -lprotobuf-lite -lpthread
metrics-0.0.1-r2183: /usr/x86_64-pc-linux-gnu/binutils-bin/2.25.51/ld.bfd.real: /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/4.9.x/../../../../lib64/libvboot_host.a(crossystem.o): relocation R_X86_64_PC32 against undefined symbol `stderr@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC
metrics-0.0.1-r2183: /usr/x86_64-pc-linux-gnu/binutils-bin/2.25.51/ld.bfd.real: final link failed: Bad value
metrics-0.0.1-r2183: clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation)
metrics-0.0.1-r2183: ninja: build stopped: subcommand failed.
metrics-0.0.1-r2183: Traceback (most recent call last):
metrics-0.0.1-r2183:   File "/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/common-mk/platform2.py", line 333, in <module>
metrics-0.0.1-r2183:     main(sys.argv[1:])
metrics-0.0.1-r2183:   File "/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/common-mk/platform2.py", line 329, in main
metrics-0.0.1-r2183:     getattr(p2, options.action)(options.args)
metrics-0.0.1-r2183:   File "/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/common-mk/platform2.py", line 270, in compile
metrics-0.0.1-r2183:     % ' '.join(map(repr, ninja_args)))
metrics-0.0.1-r2183: AssertionError: Error running: 'ninja' '-C' '/var/cache/portage/chromeos-base/metrics/out/Default' '-j' '32' 'all'
metrics-0.0.1-r2183:  * ERROR: chromeos-base/metrics-0.0.1-r2183::chromiumos failed (compile phase):
metrics-0.0.1-r2183:  *   (no error message)
metrics-0.0.1-r2183:  * 
metrics-0.0.1-r2183:  * Call stack:
metrics-0.0.1-r2183:  *     ebuild.sh, line   93:  Called src_compile
metrics-0.0.1-r2183:  *   environment, line 3582:  Called platform_src_compile
metrics-0.0.1-r2183:  *   environment, line 3182:  Called platform 'compile' 'all'
metrics-0.0.1-r2183:  *   environment, line 3137:  Called die
metrics-0.0.1-r2183:  * The specific snippet of code:
metrics-0.0.1-r2183:  *       "${cmd[@]}" || die
metrics-0.0.1-r2183:  * 
metrics-0.0.1-r2183:  * If you need support, post the output of `emerge --info '=chromeos-base/metrics-0.0.1-r2183::chromiumos'`,
metrics-0.0.1-r2183:  * the complete build log and the output of `emerge -pqv '=chromeos-base/metrics-0.0.1-r2183::chromiumos'`.
metrics-0.0.1-r2183:  * The complete build log is located at '/var/log/portage/chromeos-base:metrics-0.0.1-r2183:20170627-004910.log'.
metrics-0.0.1-r2183:  * For convenience, a symlink to the build log is located at '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/temp/build.log'.
metrics-0.0.1-r2183:  * The ebuild environment file is located at '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/temp/environment'.
metrics-0.0.1-r2183:  * Working directory: '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/metrics'
metrics-0.0.1-r2183:  * S: '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/metrics'
metrics-0.0.1-r2183: >>> Failed to emerge chromeos-base/metrics-0.0.1-r2183, Log file:
metrics-0.0.1-r2183: >>>  '/var/log/portage/chromeos-base:metrics-0.0.1-r2183:20170627-004910.log'
metrics-0.0.1-r2183: 
metrics-0.0.1-r2183:  * Messages for package chromeos-base/metrics-0.0.1-r2183:
metrics-0.0.1-r2183: 
metrics-0.0.1-r2183:  * ERROR: chromeos-base/metrics-0.0.1-r2183::chromiumos failed (compile phase):
metrics-0.0.1-r2183:  *   (no error message)
metrics-0.0.1-r2183:  * 
metrics-0.0.1-r2183:  * Call stack:
metrics-0.0.1-r2183:  *     ebuild.sh, line   93:  Called src_compile
metrics-0.0.1-r2183:  *   environment, line 3582:  Called platform_src_compile
metrics-0.0.1-r2183:  *   environment, line 3182:  Called platform 'compile' 'all'
metrics-0.0.1-r2183:  *   environment, line 3137:  Called die
metrics-0.0.1-r2183:  * The specific snippet of code:
metrics-0.0.1-r2183:  *       "${cmd[@]}" || die
metrics-0.0.1-r2183:  * 
metrics-0.0.1-r2183:  * If you need support, post the output of `emerge --info '=chromeos-base/metrics-0.0.1-r2183::chromiumos'`,
metrics-0.0.1-r2183:  * the complete build log and the output of `emerge -pqv '=chromeos-base/metrics-0.0.1-r2183::chromiumos'`.
metrics-0.0.1-r2183:  * The complete build log is located at '/var/log/portage/chromeos-base:metrics-0.0.1-r2183:20170627-004910.log'.
metrics-0.0.1-r2183:  * For convenience, a symlink to the build log is located at '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/temp/build.log'.
metrics-0.0.1-r2183:  * The ebuild environment file is located at '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/temp/environment'.
metrics-0.0.1-r2183:  * Working directory: '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/metrics'
metrics-0.0.1-r2183:  * S: '/var/tmp/portage/chromeos-base/metrics-0.0.1-r2183/work/metrics-0.0.1/platform2/metrics'
=== Complete: job metrics-0.0.1-r2183 (0m14.3s) ===