Applied Makefile.darwin patch and recompiled.
Output from make check now:
======================
All 98 tests passed.
======================
Also, please check
how file(1) describes refint.so now, and whether it changes after
re-making with the patch. I get
refint.so: Mach-O bundle ppc
Before patch:
$ file ./contrib/spi/refint.so
./contrib/spi/refint.so: Mach-O bundle ppc
After patch:
$ file ./contrib/spi/refint.so
./contrib/spi/refint.so: Mach-O 64-bit bundle ppc64
Thanks for all of your help, Tom. It is greatly appreciated.