Emerge

Unpack a ebuild modify code / headers /config then continue to build / install

ebuild /full/path/to/ebuild/package.ebuild unpack
.. do the changes ..
ebuild /full/path/to/ebuild/package.ebuild compile install qmerge

emerge -P gentoo-sources

ebuild /usr/portage/app-emulation/vmware-workstation/vmware-workstation-5.5.4.44386.ebuild digest
ebuild /usr/portage/app-emulation/vmware-modules/vmware-modules-1.0.0.15-r1.ebuild digest

emerge -vpe world

qlist -I -C x11-drivers

eix -I --only-names xf86-input | xargs emerge -1

qlist -I -C x11-drivers  | xargs emerge -1
module-rebuild rebuild

mkdir -p /etc/portage/patches/x11-drivers/nvidia-drivers-319.32 wget https://bugzilla.kernel.org/attachment.cgi?id=102881 -O /etc/portage/patches/x11-drivers/nvidia-drivers-319.32/Linux-3.10.patch emerge nvidia-drivers