diff --git a/common/util.h b/common/util.h
index 6e76a71e..f0caaa08 100644
--- a/common/util.h
+++ b/common/util.h
@@ -28,6 +28,7 @@
 #include <stdbool.h>
 #include <stdarg.h>
 #include <assert.h>
+#include <alloca.h>
 
 /** A list of possible position, not sex related */
 typedef enum
@@ -60,6 +61,10 @@ typedef struct
 #define ssizeof(foo)            (ssize_t)sizeof(foo)
 #define countof(foo)            (ssizeof(foo) / ssizeof(foo[0]))
 
+#define p_alloca(type, count)                                \
+        ((type *)memset(alloca(sizeof(type) * (count)),      \
+                        0, sizeof(type) * (count)))
+
 #define p_alloc_nr(x)           (((x) + 16) * 3 / 2)
 #define p_new(type, count)      ((type *)xmalloc(sizeof(type) * (count)))
 #define p_clear(p, count)       ((void)memset((p), 0, sizeof(*(p)) * (count)))