Maybe include unistd.h.

diff --git a/src/ralloc.c b/src/ralloc.c
index 183db755412fd663d56ef8f290c11572d6ea7434..38adc795a9140844823cbaf057d79d238aa7530d 100644 (file)
--- a/src/ralloc.c
+++ b/src/ralloc.c
@@ -28,7 +28,9 @@ Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
 #include "lisp.h"              /* Needed for VALBITS.  */
-
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
 #undef NULL
 
 /* The important properties of this type are that 1) it's a pointer, and