$ qlist sys-kernel/linux-headers | grep "\.install" /usr/include/asm/..install.cmd /usr/include/asm/.install /usr/include/mtd/..install.cmd /usr/include/mtd/.install /usr/include/rdma/..install.cmd /usr/include/rdma/.install /usr/include/linux/can/..install.cmd /usr/include/linux/can/.install /usr/include/linux/dvb/..install.cmd /usr/include/linux/dvb/.install /usr/include/linux/spi/..install.cmd /usr/include/linux/spi/.install /usr/include/linux/usb/..install.cmd /usr/include/linux/usb/.install /usr/include/linux/hdlc/..install.cmd /usr/include/linux/hdlc/.install /usr/include/linux/isdn/..install.cmd /usr/include/linux/isdn/.install /usr/include/linux/nfsd/..install.cmd /usr/include/linux/nfsd/.install /usr/include/linux/raid/..install.cmd /usr/include/linux/raid/.install /usr/include/linux/netfilter_arp/..install.cmd /usr/include/linux/netfilter_arp/.install /usr/include/linux/netfilter_bridge/..install.cmd /usr/include/linux/netfilter_bridge/.install /usr/include/linux/netfilter/..install.cmd /usr/include/linux/netfilter/.install /usr/include/linux/netfilter_ipv4/..install.cmd /usr/include/linux/netfilter_ipv4/.install /usr/include/linux/netfilter_ipv6/..install.cmd /usr/include/linux/netfilter_ipv6/.install /usr/include/linux/..install.cmd /usr/include/linux/.install /usr/include/linux/byteorder/..install.cmd /usr/include/linux/byteorder/.install /usr/include/linux/tc_ematch/..install.cmd /usr/include/linux/tc_ematch/.install /usr/include/linux/tc_act/..install.cmd /usr/include/linux/tc_act/.install /usr/include/linux/sunrpc/..install.cmd /usr/include/linux/sunrpc/.install /usr/include/video/..install.cmd /usr/include/video/.install /usr/include/..install.cmd /usr/include/.install /usr/include/asm-generic/..install.cmd /usr/include/asm-generic/.install I don't think those files should be there.
fixed with 2.6.27-r1 ... thanks for the report