[util] reverse linked list

src/util/functions.c

@@ -0,0 +1,14 @@
+#include "functions.h"
+#include <stddef.h>
+
+void* ax__reverse_list(void* l)
+{
+    void* next;
+    void* rev = NULL;
+    for (void** list = l; list != NULL; list = next) {
+        next = *list;
+        *list = rev;
+        rev = list;
+    }
+    return rev;
+}

src/util/functions.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void* ax__reverse_list(void* list);