Problems compiling 6.5.3 on solaris 2.6

I'm trying to get postgresql 6.5.3 working on solaris 2.6 with gcc, and it's
just not cooperating.

First of all, during the configure process, I see:

--(snip!)--
checking for ANSI C header files... grep: can't open conftest.out
no
checking for sys/wait.h that is POSIX.1 compatible... yes
checking for arpa/inet.h... grep: can't open conftest.out
yes
checking for crypt.h... grep: can't open conftest.out
yes
checking for dld.h... grep: can't open conftest.out
yes
--(snip!)--

..and a whole bunch more (endian.h, float.h, getopt.h, that whole block
down to pwd.h), which scares me.

Then, further on, it gets down to the index stuff, and I get this:

--(snip!)--
gcc -I../../../include -I../../../backend -Wall -Wmissing-prototypes -I..
/.. -c -o istrat.o istrat.c
istrat.c: In function `OperatorRelationFillScanKeyEntry':
istrat.c:492: `F_OIDEQ' undeclared (first use in this function)
istrat.c:492: (Each undeclared identifier is reported only once
istrat.c:492: for each function it appears in.)
istrat.c: In function `IndexSupportInitialize':
istrat.c:558: `F_OIDEQ' undeclared (first use in this function)
gmake[3]: *** [istrat.o] Error 1
gmake[3]: Leaving directory `/tmp/postgresql-6.5.3/src/backend/access/index'
gmake[2]: *** [submake] Error 2
gmake[2]: Leaving directory `/tmp/postgresql-6.5.3/src/backend/access'
gmake[1]: *** [access.dir] Error 2
gmake[1]: Leaving directory `/tmp/postgresql-6.5.3/src/backend'
gmake: *** [all] Error 2
--(snip!)--

Any ideas what should be defining F_OIDEQ?

I appreciate any help you can offer.

Thanks,