[oe] Amend recipes which do not contain a (new) target machine in COMPATIBLE_MACHINE

[Hauser, Wolfgang (external)]

>I guess you might not be able to append to COMPATIBLE_MACHINE from
>amend.inc since amend.bbclass probably doesn't get run early enough.
>But you should be able to use COMPATIBLE_MACHINE_append_pn-... in your
>layer.conf, or COMPATIBLE_MACHINE += in a .bbappend file.  Are those
not
>working for you?

The .bbappend files don't work with bitbake version 1.10.2 which is
required by OE release 2011.03.

I want to use linux-omap-psp_2.6.32.bb as kernel recipe, how is the
exact format for COMPATIBLE_MACHINE_append_pn-... ?

I tried COMPATIBLE_MACHINE_append_linux-omap-psp = "mymachine" and
COMPATIBLE_MACHINE_append_pn-linux-omap-psp = "mymachine", both don't
work for me.