builtin isinf in v4 causing linking problem on Solaris

[Sigmund Straumsnes <Sigmund.Straumsnes@xxxxxxxxx>]

Hi,
since installing v4.0 of GCC, I get link failures (GNU ld).
It seems that isinf is defined as a builtin, but since it's not present on 
Solaris (9), linking fails.

I've tried to run with -fno-builtin-isinf, but then I get internal 
compiler failure.

Is this related to bug 20558?
Is there a workaround for this?

Thanks,
Sigmund