The addition of rint() (by Peter Schneider-Kamp; I forgot to mention

that before) in the previous patch has one problem; rint() is not in
the C math library on all platforms (e.g. not for VC++).  Make it
conditional on HAVE_RINT.

Doc/lib/libmath.tex

@@ -95,6 +95,7 @@ Return \code{\var{x}**\var{y}}.
 
 \begin{funcdesc}{rint}{x, y}
 Return the integer nearest to \var{x} as a real.
+(Only available on platforms where this is in the standard C math library.)
 \end{funcdesc}
 
 \begin{funcdesc}{sin}{x}