PMM and liballoc port

kernel/amd64/bootmain.c

@@ -1,11 +1,18 @@
 #include <limine/limine.h>
 #include <amd64/init.h>
 #include <sys/debug.h>
+#include <mm/pmm.h>
+#include <mm/liballoc.h>
 
 void bootmain(void) {
   amd64_init();
-
   DEBUG("Hello from amd64!\n");
 
+  pmm_init();
+
+  int *a = malloc(sizeof(int));
+  *a = 6969;
+  DEBUG("a=%p, *a=%d\n", a, *a);
+
   for (;;);
 }