The current actual version for Cython is 0.9.6.12 (as of 02/13). The old ebuild seems to work flawlessly - except that there are no *.c files in the Demos folder anymore.
Created attachment 146398 [details, diff] cython-0.9.6.12.ebuild patch The patch removing the *.c files from the examples to be installed.
in CVS, thanks for reporting.