all >=virtual/linux-sources-2.6.33 optional dependеnd app-arch/lzop in build time. If use KERNEL_LZO=y config options, build kernel failure with the message: Building modules, stage 2. CC arch/x86/boot/video-vesa.o CC arch/x86/boot/video-bios.o HOSTCC arch/x86/boot/tools/build LZO arch/x86/boot/compressed/vmlinux.bin.lzo /bin/sh: lzop: command not found make[2]: *** [arch/x86/boot/compressed/vmlinux.bin.lzo] lzop utility contained in app-arch/lzop package, but kernel ebuild not intalled it.
lzop is a package outside the kernel