diff --git a/src/ChangeLog b/src/ChangeLog
index 5d6eb0a435b..d7dc454c3dc 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,7 @@
 2011-04-16  Paul Eggert  <eggert@cs.ucla.edu>
 
+	* eval.c: Include <stdio.h>, for vsnprintf on non-GNU/Linux hosts.
+
 	* data.c (arith_error): Mark with NO_RETURN if it doesn't return.
 
 	* alloc.c (bytes_used_when_full, SPARE_MEMORY, BYTES_USED):
diff --git a/src/eval.c b/src/eval.c
index c068f5f3fbf..b843ca5b2ec 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -20,6 +20,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include <limits.h>
 #include <setjmp.h>
+#include <stdio.h>
 #include "lisp.h"
 #include "blockinput.h"
 #include "commands.h"