SunOS 4.0 frexp() bug

[Doug Gwyn]

We recently tried using a Sun-4 for the first time and immediately
discovered that frexp(0.0,...) goes into an infinite loop.  The
only SunOS source code I could find around here seems to indicate
that the frexp.c that I assume was used for the SPARC machine was
obtained via BSD, which is why I'm posting this here.

One wonders how frexp() could possibly have passed its pre-release
tests..