Added support for Gentoo.

bin/compile-nagios-plugins

bin/compile-nrpe

bin/install-local

bin/install-nrpe

bin/utils/functions.sh

rules/gentoo/config-nrpe.sh

rules/gentoo/nrpe-host-auto.sh

site-rules/lysator/config-nrpe-posthook.sh

site-rules/lysator/gentoo/compile-nagios-plugins-prehook.sh

site-rules/lysator/gentoo/compile-nrpe-prehook.sh

site-rules/lysator/gentoo/install-nagios-plugins-prehook.sh

site-rules/lysator/gentoo/install-nrpe-prehook.sh

site-rules/lysator/gentoo/os

site-rules/lysator/gentoo/setup-env.sh

site-rules/lysator/solaris10/config-nrpe-posthook.sh