linux uart driver

Hi,

I'm exploring writing a simple uart driver for linux in order to get terminal_mux working on linux. When I disable the linux spec check in terminal_mux.run, the build always picks up:

Program drivers/uart/spec/x86/uart_drv

even though I created a drivers/uart/spec/linux/

and changed drivers/uart/spec/linux/target.mk to read

REQUIRES = linux

and the etc/specs.conf in the build directory to read:

SPECS += linux x86_64

I'd like to know how I can get the build to say

Program drivers/uart/spec/linux/uart_drv

Thanks,

--prashanth