undefined reference in system library on netbsd-9/sparc

["John D. Baker" <jdbaker%consolidated.net@localhost>]

Building "sysutils/apcupsd" on NetBSD/sparc-9.0_BETA fails linking with:

[...]
  LD    src/apcupsd
ld: /usr/lib/libsupc++.a(eh_throw.o):(.text+0x78): undefined reference to `__gnu_cxx::__exchange_and_add(int volatile*, int)'


I have an old binary package from the last time I built apcupsd on sparc.
It reports OS_VERSION of 8.99.26.  So whatever the gcc/g++ version and
libraries in use at that time, it worked fine.

Clues?

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