Index: pss-mgf1.c
--- pss-mgf1.c.orig
+++ pss-mgf1.c
@@ -38,6 +38,7 @@
 #include "pss-mgf1.h"
 
 #include <assert.h>
+#include <stdlib.h>  /* alloca */
 #include <string.h>
 
 #include "nettle-internal.h"