BSD unsetenv(), strcasecmp(), (what are they?)

[Lyle Seaman]

I've been trying to build sendmail 5.61 on SunOS 3.5 (I can't
afford the upgrade, ok?).  I find I get two unresolved references
I'm not familiar with.  I assume this is because they are new to
BSD and aren't in SunOS.  One is strcasecmp which I assume is
compare string case-not-significant.  The other is unsetenv().
I know this is a c-shell builtin, which removes the given 
variable from the environment, but how would I write this
routine?  Would I manipulate the environment pointer (third
argument to main()), or use putenv("TZ=")  or what?

Also - someone must be more familiar with the BSD family tree;
what version of BSD is SunOS derived from?

please e-mail.  (I do read this group, but email anyway)
Thanks,

-- 
Lyle                     sendmail.cf under construction, pardon the From:
lws at comm.wang.com        (or, uunet!comm.wang.com!lws)  (508) 967-2322