Building -current on -stable box => install broken?

Hi,

I've been building -current on a 4.x buildmachine on a daily basis for
about a year. The /usr/obj and /usr/src directories are nfs exported to 
a testmachine running -current.
After I came back from holiday a few days ago I noticed that the install
on the -current machine gave me the following error:

caliban# make installworld

--------------------------------------------------------------
>>> Building an up-to-date make(1)
--------------------------------------------------------------
make: don't know how to make /usr/include/sys/inttypes.h. Stop
*** Error code 2

Stop in /usr/build/current/usr/src.
*** Error code 1

Stop in /usr/build/current/usr/src.

Now, in -stable there is a /usr/include/sys/inttypes.h, but on -current
this file is in /usr/include/inttypes.h (at least in the last installed
version of -current I have).
So far I haven't found any clues in the archieves. Did I miss something
or is something broken (the build- installprocess I describe is still
supported right ?)

-Ruben