Install this version:
emerge -a =app-exploits/linux-exploit-suggester-20140519
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask
emerge
autounmask =app-exploits/linux-exploit-suggester-20140519
Or alternatively:
emerge --autounmask-write -a =app-exploits/linux-exploit-suggester-20140519
./linux-exploit-suggester-99999999.ebuild