In Portage tree since six weeks, please stabilise. There is bug 368227 which seems to happen on prefix only, so it shouldn't be an obstacle for stabilisation on native arches. However, in order to verify that this really isn't a problem, please emerge gnuplot with USE=cairo and test with the recipe given in bug 368227 comment #1. Thank you in advance.
amd64 ok
amd64 done. Thanks Agostino
x86 stable
alpha/ia64/s390/sparc stable
ppc/ppc64 done
Stable for HPPA and closing.