Delete abs function

Signed-off-by: Gavin Howard <gavin@yzena.com>

cf.bc

@@ -11,7 +11,6 @@
 
 # Borrowed from funcs.bc
 define int(x) { auto os;os=scale;scale=0;x/=1;scale=os;return(x) }
-define abs(x) { if(x<0)return(-x)else return(x) }
 
 # Borrowed from output_formatting.bc
 define newline() { print "\n" }

funcs.bc

@@ -46,9 +46,6 @@ define frac(x) {
   scale=os;return(x-xx)
 }
 
-# Absolute value of x
-define abs(x) { if(x<0)return(-x)else return(x) }
-
 # Sign of x
 define sgn(x) { if(x<0)return(-1)else if(x>0)return(1);return(0) }