add missing prototypes for trunc/truncf.

src/include/math.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: math.h,v 1.12 2006/05/05 20:10:25 otto Exp $	*/
+/*	$OpenBSD: math.h,v 1.13 2006/07/12 06:43:31 brad Exp $	*/
 /*
  * ====================================================
  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
@@ -141,6 +141,8 @@ extern double fabs(double);
 extern double floor(double);
 extern double fmod(double, double);
 
+extern double trunc(double);
+
 #if __BSD_VISIBLE || __XPG_VISIBLE
 extern double erf(double);
 extern double erfc(double);
@@ -234,6 +236,8 @@ extern float fabsf(float);
 extern float floorf(float);
 extern float fmodf(float, float);
 
+extern float truncf(float);
+
 extern float erff(float);
 extern float erfcf(float);
 extern float gammaf(float);