The culprit is the "make %{_smp_flags}" in the spec file.

Unfortunately, it appears that bind's current makefile has a couple of race
conditions, which can sometimes fail if the -j option to make is used:

gcc -O2 -march=i386 -mcpu=i686 -I/home/mrsam/src/rpm/BUILD/bind-9.2.0 -I.
-I/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib/dns/include -I../../lib/dns/include
-I../../lib/dns/sec/dst/include
-I/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib/isc/include -I../../lib/isc
-I../../lib/isc/include -I../../lib/isc/unix/include
-I../../lib/isc/pthreads/include -D_REENTRANT -W -Wall -Wmissing-prototypes
-Wcast-qual -Wwrite-strings -c a6.c  -fPIC -DPIC -o .libs/a6.lo
In file included from
/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib/dns/include/dns/a6.h:28,
                 from a6.c:24:
/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib/dns/include/dns/types.h:162:64:
dns/enumtype.h: No such file or directory
/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib/dns/include/dns/types.h:163:65:
dns/enumclass.h: No such file or directory
make[2]: *** [a6.lo] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory `/mnt/sdb5/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib/dns'
make[1]: *** [subdirs] Error 1
make[1]: Leaving directory `/mnt/sdb5/home/mrsam/src/rpm/BUILD/bind-9.2.0/lib'
make: *** [subdirs] Error 1
error: Bad exit status from /var/tmp/rpm-tmp.95607 (%build)

The two include files in question, dns/enumtype.h and dns/enumclass.h, are
automatically generated by other rules in that Makefile, and it appears that the
correct dependencies for building with the -j options are not present.