Index: include/yalecad/base.h
--- include/yalecad/base.h.orig
+++ include/yalecad/base.h
@@ -51,7 +51,7 @@ REVISIONS:  Feb 25, 1989 - modified round macro so res
 #ifndef STDIO_H
 #define STDIO_H
 #include <stdio.h> 
-#ifdef linux
+#if defined(linux) || defined(__OpenBSD__)
 #include <stdlib.h>	/* needed for atof() */
 #endif
 #endif
@@ -125,7 +125,7 @@ typedef long SHORT_LONG ;
 
 #include <yalecad/mac.h>
 
-#elif defined(linux) || defined(ultrix)
+#elif defined(linux) || defined(ultrix) || defined(__OpenBSD__)
 
 #ifndef	_LIMITS_H_
 #include <limits.h>
