refactor(libc): move Lua an DOOM stubs into shared libc modules

src/userland/libc/fcntl.h

@@ -0,0 +1,15 @@
+#ifndef BOREDOS_LIBC_FCNTL_H
+#define BOREDOS_LIBC_FCNTL_H
+
+#include "sys/types.h"
+
+#define O_RDONLY 0x0000
+#define O_WRONLY 0x0001
+#define O_RDWR   0x0002
+#define O_CREAT  0x0040
+#define O_TRUNC  0x0200
+#define O_APPEND 0x0400
+
+int open(const char *pathname, int flags, ...);
+
+#endif