trivial diff: math.m warning/documentation fix

[Andrew Bromage]

G'day all.

Already committed.

Cheers,
Andrew Bromage


Estimated hours taken: 0.4

library/math.m:
	Include mercury_trace.h since we use MR_trace_report (this
	fixes a compiler warning).
	A couple of minor documentation fixes/enhancements.


Index: math.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/library/math.m,v
retrieving revision 1.16
diff -u -t -u -r1.16 math.m
--- math.m	1998/09/09 02:35:15	1.16
+++ math.m	1998/09/21 00:34:47
@@ -199,6 +199,11 @@
 
         /*
         ** Mathematical constants.
+        **
+        ** The maximum number of significant decimal digits which
+        ** can be packed into an IEEE-754 extended precision
+        ** floating point number is 18.  Therefore 20 significant
+        ** decimal digits for these constants should be plenty.
         */
 
         #define ML_FLOAT_E              2.7182818284590452354
@@ -211,6 +216,7 @@
 
 :- pragma c_code("
 
+        #include <mercury_trace.h>
         #include <stdio.h>
 
         /*
@@ -884,7 +890,7 @@
 ").
 
 %
-% math__cos(X, Sin) is true if Cos is the cosine of X.
+% math__cos(X, Cos) is true if Cos is the cosine of X.
 %
 :- pragma c_code(math__cos(X::in, Cos::out),
                 [will_not_call_mercury, thread_safe], "