diff --git a/math_private.h b/math_private.h
--- a/math_private.h
+++ b/math_private.h
@@ -13,16 +13,17 @@
  * from: @(#)fdlibm.h 5.1 93/09/24
  * $FreeBSD$
  */
 
 #ifndef _MATH_PRIVATE_H_
 #define	_MATH_PRIVATE_H_
 
 #include <bit>
+#include <cfloat>
 #include <stdint.h>
 #include <sys/types.h>
 
 #include "fdlibm.h"
 
 /*
  * The original fdlibm code used statements like:
  *	n0 = ((*(int*)&one)>>29)^1;		* index of high word *