Build failure of m4 on powerpc

Hello.

I applied the patch from Collin Funk to fix the build problem on
alpha, and now I have this build failure on powerpc:

FAIL: test-float-h
==================

test-float-h.c:460: assertion 'x <= 1.0L' failed
FAIL test-float-h (exit status: 134)

There is also a build failure on ppc64, but it's similar,
so I'm not going to report it as a different bug.

Details here:

https://buildd.debian.org/status/package.php?p=m4

Thanks.