Remove C++ checks from kernel main file

src/kern.c

-#if !defined(__cplusplus)
 #include <stdbool.h> /* C doesn't have booleans by default. */
-#endif
 #include <stddef.h>
-
-/* Check if the compiler thinks we are targeting the wrong operating system. */
-#if defined(__linux__)
-#error "You are not using a cross-compiler, you will most certainly run into trouble"
-#endif
-
-/* This tutorial will only work for the 32-bit ix86 targets. */
-#if !defined(__i386__)
-#error "This tutorial needs to be compiled with a ix86-elf compiler"
-#endif
-
 #include <stdint.h>
 
 #include "serial.h"
@@ -37,7 +24,7 @@ void kernel_main() {
 
     // Enable paging of memory. For now there is only one virtual
     // memory space defined by page_dir
-    uint32_t* page_dir;
+    page_directory_entry* page_dir;
     page_dir = initiate_directory();
     initiate_page_table(page_dir);
     loadPageDirectory(page_dir);