diff --git a/src/doprnt.c b/src/doprnt.c
index 9afdd5ae856..2e8f498ddcf 100644
--- a/src/doprnt.c
+++ b/src/doprnt.c
@@ -29,6 +29,14 @@ Boston, MA 02111-1307, USA.  */
 #include <float.h>
 #endif
 
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
 #include "lisp.h"
 
 #ifndef DBL_MAX_10_EXP