Mine

creating beryl
gmake -C /var/tmp/portage/x11-wm/beryl-core-0.2.1/work/beryl-mesa/src/
gmake[3]: Entering directory `/var/tmp/portage/x11-wm/beryl-core-0.2.1/work/beryl-mesa/src'
Making sources for linux-dri
mkdir ../lib
Error expanding embedded variable.
gmake[3]: *** [subdirs] Error 1
gmake[3]: Leaving directory `/var/tmp/portage/x11-wm/beryl-core-0.2.1/work/beryl-mesa/src'
gmake[2]: *** [/var/tmp/portage/x11-wm/beryl-core-0.2.1/work/beryl-mesa/lib/libGL.a] Error 2
gmake[2]: Leaving directory `/var/tmp/portage/x11-wm/beryl-core-0.2.1/work/beryl-core-0.2.1/src'
gmake[1]: *** [all-recursive] Error 1
gmake[1]: Leaving directory `/var/tmp/portage/x11-wm/beryl-core-0.2.1/work/beryl-core-0.2.1'
gmake: *** [all] Error 2