-current broken when src is on NFS

I am seeing the following breakage when building -current and the source is on NFS

make -j 4 buildworld
...
--- rescue.all__D ---
--- rescue ---
MAKEOBJDIRPREFIX=/usr/obj/src/FreeBSD-HEAD/rescue/rescue make -f rescue.mk exe
--- sbin.all__D ---
--- pfctl_qstats.o ---
cc  -O2 -pipe   -Wall -Wmissing-prototypes -Wno-uninitialized -Wstrict-prototypes -DENABLE_ALTQ -I/src/FreeBSD-HEAD/sbin/pfctl -DWITH_INET6 -DWITH_INET -std=gnu99 -fstack-protector -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-switch -Wno-switch-enum -Wno-knr-promoted-parameter -Qunused-arguments -c /src/FreeBSD-HEAD/sbin/pfctl/pfctl_qstats.c -o pfctl_qstats.o
--- rescue.all__D ---
--- cat_stub.c ---
echo "int _crunched_cat_stub(int argc, char **argv, char **envp){return main(argc,argv,envp);}" >cat_stub.c
make[5]: make[5]: don't know how to make /usr/obj/src/FreeBSD-HEAD/rescue/rescue//src/FreeBSD-HEAD/bin/cat/cat.o. Stop

make[5]: stopped in /usr/obj/src/FreeBSD-HEAD/rescue/rescue
*** [rescue] Error code 2

I copied this source tree to /usr/src (UFS) and it built fine - I guess it's possible it is barfing on the path name but I figure someone else would have noticed that.

The NFS server is running 10.0-RELEASE and the NFS client is running -current r285456, lockd is running and seems to be working (e.g., cat -l works)

--
Daniel O'Connor
"The nice thing about standards is that there
are so many of them to choose from."
 -- Andrew Tanenbaum
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