faster lrint and llrint functions

A faster workaround for spurious inexact exceptions
when the result cannot be represented. The old code
actually could be wrong, because gcc reordered the
integer conversion and the exception check.

src/math/llrint.c

@@ -1,8 +1,8 @@
-#define type            double
-#define roundit         rint
-#define dtype           long long
-#define fn              llrint
-
-#include "lrint.c"
+#include <math.h>
 
+/* assumes LLONG_MAX > 2^53, see comments in lrint.c */
 
+long long llrint(double x)
+{
+	return rint(x);
+}