Fix double free error when expanding lists

src/main/c/util/list.h

@@ -4,6 +4,8 @@
 #include <stddef.h>
 #include <stdlib.h>
 
+#include "./mem.c"
+
 #define INITIAL_LIST_SIZE 20
 #define LIST_GROWTH_RATE 1.5
 
@@ -87,8 +89,6 @@
       new_data[i] = 0;                                                                            \
     }                                                                                             \
                                                                                                   \
-    free(buf->data);                                                                              \
-                                                                                                  \
     buf->data = new_data;                                                                         \
     buf->size = new_size;                                                                         \
   }                                                                                               \