fix to sendmail / save _environ pointer

[Chris Torek]

A wonderful example of why using

	write(fd, &edata, sbrk(0) - &edata)

is a Bad Thing.  Both rogue and sendmail do this (rogue does it with
an encryption though) and both programs have various related bugs.

Yes, it's fast, but ..... eeeeauuyuck.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at maryland