[yocto] best way to add conditional configure option

[Neuer User]

Hi

I have a simple recipe (libcec) that I would like to add an additional
configure option to, depending if the machine is an imx6 based one.

How would I do that best?

Here is the recipe:

---------------------------------------------
SUMMARY = "USB CEC Adaptor communication Library with patches for imx6"
HOMEPAGE = "http://libcec.pulse-eight.com/"

LICENSE = "GPLv2+"
LIC_FILES_CHKSUM = "file://COPYING;md5=5e8e16396992369f73f3d28875f846da"

DEPENDS = "udev lockdev"

PV = "2.4.1"

SRCREV = "42c3c07a79b8155635851c2eed9558b221b89047"
SRC_URI = "git://github.com/xbmc-imx6/libcec.git"

S = "${WORKDIR}/git"

inherit autotools pkgconfig

# cec-client and xbmc need the .so present to work :(
FILES_${PN} += "${libdir}/*.so"
INSANE_SKIP_${PN} = "dev-so"
---------------------------------------------

The conditional configure option is "--enable-imx6".

Thanks for helping

Michael