Releng_6 suddenly no longer -j safe

[[LoN]Kamikaze]

Last time I built a kernel on Releng_6 (only a couple of days ago)
everything was fine with "-j 4".
Now buildkernel stops, this is an example:

===> sound/driver/als4000 (depend)
awk -f @/tools/makeobjops.awk @/kern/device_if.m -h
machine -> /usr/src/sys/i386/include
awk: can't open file @/tools/makeobjops.awk
 source line number 1 source file @/tools/makeobjops.awk
 context is
	>>>   <<<
*** Error code 2
@ -> /usr/src/sys
1 error
...

Where it stops is random (I suppose it sometimes is accidentally
built in the right order), but the error is always similar.