Use prettier #defines for attributes

kernel/amd64/bootmain.c

@@ -1,4 +1,5 @@
 #include <amd64/init.h>
+#include <aux/compiler.h>
 #include <limine/limine.h>
 #include <mm/liballoc.h>
 #include <mm/pmm.h>
@@ -7,8 +8,7 @@
 
 #define UACPI_MEMORY_BUFFER_MAX 4096
 
-__attribute__ ((
-    aligned (16))) static uint8_t uacpi_memory_buffer[UACPI_MEMORY_BUFFER_MAX];
+ALIGNED (16) static uint8_t uacpi_memory_buffer[UACPI_MEMORY_BUFFER_MAX];
 
 void bootmain (void) {
   amd64_init ();