Via: uk.ac.exeter.exua; Wed, 30 Sep 1992 12:33:16 +0100
From: John Cremona (Maths) <cremona AT vortex1 DOT exeter DOT ac DOT uk>
Date: Wed, 30 Sep 92 12:32:45 BST
To: ESCHN705 AT RZ DOT Braunschweig DOT PTB DOT DBP DOT de
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: abs()olutely hopeless?

Try putting 

#include <builtin.h>

in your program.  This includes math.h and also defines abs and other
similar functions for all the relevant types.

John Cremona
Exeter
UK