addind more important kernel files and also fixing bugs

kernel/syscalls.h

@@ -1,6 +1,17 @@
 #ifndef SYSCALLS_H
 #define SYSCALLS_H
 
+// Syscall numbers
+typedef enum {
+    SYSCALL_INIT = 0,
+    SYSCALL_SPAWN,
+    SYSCALL_YIELD
+} syscall_code_t;
+
+// Syscall dispatcher
 void syscall_handler();
 
+// Syscall interface
+void syscall(int code, ...);
+
 #endif // SYSCALLS_H