reimplement compare function for quicksort

include/quicksort.h

@@ -3,6 +3,6 @@
 
 #include "types.h"
 
-int lsort_quicksort(lsort_array* array);
+int lsort_quicksort(lsort_array* array, int_function_pointer compare_function);
 
 #endif

include/types.h

@@ -4,6 +4,7 @@
 #include <stddef.h>
 #include "string.h"
 
+
 typedef struct {
     const char *buf;
     size_t len;
@@ -13,6 +14,8 @@ typedef struct {
     int key;
     void* value;
 } lsort_item;
+typedef int (*int_function_pointer)(lsort_item*, lsort_item*);
+
 
 typedef struct {
     size_t count;