Mine

if i686-pc-linux-gnu-gcc -DHAVE_CONFIG_H -I. -I. -I../..  -I../..  -fPIC -Wall -march=athlon64 -O2 -pipe -fomit-frame-pointer -Wno-unused-function -MT icp_a106.o -MD -MP -MF ".deps/icp_a106.Tpo" \
  -c -o icp_a106.o `test -f 'icp_a106.c' || echo './'`icp_a106.c; \
then mv -f ".deps/icp_a106.Tpo" ".deps/icp_a106.Po"; \
else rm -f ".deps/icp_a106.Tpo"; exit 1; \
fi
In file included from /usr/include/linux/i2c-dev.h:28,
                 from hd44780-i2c.c:62:
/usr/include/linux/i2c.h:66: error: array type has incomplete element type
make[3]: *** [hd44780-i2c.o] Error 1
make[3]: *** Waiting for unfinished jobs....
make[3]: Leaving directory `/var/tmp/portage/lcdproc-0.5.1/work/lcdproc-0.5.1/server/drivers'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/var/tmp/portage/lcdproc-0.5.1/work/lcdproc-0.5.1/server'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/var/tmp/portage/lcdproc-0.5.1/work/lcdproc-0.5.1'
make: *** [all] Error 2

!!! ERROR: app-misc/lcdproc-0.5.1 failed.
Call stack:
  ebuild.sh, line 1546:   Called dyn_compile
  ebuild.sh, line 937:   Called src_compile
  lcdproc-0.5.1.ebuild, line 136:   Called die