Irix 6.2 and PGSQL 6.5.1

I have been trying to compile pgqsl 6.5 for a couple of weeks on my sgi
running irix 6.2 and using gcc 2.8.1 (i don't have sgi's compiler).  I
could never get it to compile and my porting skills are not good.  I
noticed today that there was a bug fix release to the source and so I
downloaded it and thought I would make another stab at it. I am
currently stuck in the build at the following error:

gmake[3]: Entering directory
`/usr/src/postgresql-6.5.1/src/backend/storage/buffer'
gcc -I../../../include -I../../../backend    -U_NO_XOPEN4 -Wall
-Wmissing-prototypes -I../..   -c s_lock.c -o s_lock.o
s_lock.c: In function `s_lock':
s_lock.c:74: warning: passing arg 1 discards `volatile' from pointer
target type
s_lock.c: At top level:
s_lock.c:149: warning: `tas_dummy' defined but not used
as: Error: /var/tmp/cca004WJ.s, line 297: undefined assembler operation:
.global
     .global tas
gmake[3]: *** [s_lock.o] Error 1

Could someone please explain this error or point me in an appropriate
direction.

-gerald