Trouble building 8.1.1 on Tru64 UNIX 5.1

While building 8.1.1 on Tru64 UNIX 5.1:
gmake[5]: Leaving directory `/opt/build/postgresql-8.1.1/src/port'
cc -O2 -ieee -msym -readonly_strings -pthread  --thread-safe
-D_REENTRANT -D_THREAD_SAFE -D_POSIX_PTHREAD_SEMANTICS -I./../include
-I. -I../../../../src/include -I/opt/TWWfsw/gettext014/include
-I/opt/TWWfsw/readline50/include -I/opt/TWWfsw/libopenssl097/include
-I/opt/TWWfsw/zlib11/include -I/opt/TWWfsw/tcl84/include
-I/opt/TWWfsw/tk84/include -DMAJOR_VERSION=4 -DMINOR_VERSION=1
-DPATCHLEVEL=1  -c -o preproc.o preproc.c
cc: Error: /usr/include/arpa/nameser_compat.h, line 154: Invalid
declarator. (declarator)
} HEADER;
--^

The problem is that /usr/include/arpa/nameser_compat.h defines a
struct named HEADER. This conflicts with the use of preproc.y in
src/interfaces/ecpg/preproc/preproc.y.

What should it be renamed to?

-- 
albert chin (china@thewrittenword.com)