add first fe_renderlist function

src/renderlist.c

@@ -0,0 +1,36 @@
+#include <fxengine/renderlist.h>
+#include <fxengine/model/object.h>
+#include <gint/std/stdlib.h>
+
+static fe_object ** list = 0;
+static int list_size = 0;
+
+int fe_renderlist_add(fe_object * const object)
+{
+    if (object==0)
+        return -1;
+    for (int i=0; i<list_size; i++)
+        if (list[i]==object)
+            return -1;
+    for (int i=0; i<list_size; i++)
+    {
+        if (list[i]==0)
+        {
+            list[i]=object;
+            return i;
+        }
+    }
+    
+    if (list==0)
+    {
+        list_size++;
+        list=malloc(sizeof(int));
+        list[0]=object;
+    }
+    else
+    {
+        list_size++;
+        list=realloc(list, list_size*sizeof(int));
+        list[list_size-1]=object;
+    }
+}