build fails on IRIX 6.5

[Bill en Dennis]

I am trying to build 6.9 on IRIX64 octane 6.5 04100803 IP30
It stops here (see below).
Anything I can change to help it along?

Thank you,
-Bill
----------------------
        CC -c -O -OPT:Olimit=0  -xansi -mips3 -n32  -I../nurbtess     
 -I../../libutil         -I../../include         -I../../../../include
  -I../../../../include/GL -I../../../.. -I../../../../exports/include
 -DSVR4   -D_SCO_DS -DLIBRARYBUILD -DNDEBUG     -KPIC patch.cc
cc-3162 CC: ERROR File = simplemath.h, Line = 57
  The function "abs(REAL)" conflicts with using-declaration of function
          "std::abs(float)".

  abs( REAL x ) { return ( x < 0.0 ) ? -x : x; }
  ^

1 error detected in the compilation of "patch.cc".
*** Error code 2 (bu21)
*** Error code 1 (bu21)
*** Error code 1 (bu21)
*** Error code 1 (bu21)
gmake[1]: *** [World] Error 1
gmake[1]: Leaving directory `/usr/people/wstan/build'
gmake: *** [World] Error 2