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

src/userland/libc/errno.h

@@ -0,0 +1,18 @@
+#ifndef BOREDOS_LIBC_ERRNO_H
+#define BOREDOS_LIBC_ERRNO_H
+
+extern int errno;
+
+#define EDOM 33
+#define ERANGE 34
+#define EINVAL 22
+#define EISDIR 21
+#define ENOENT 2
+#define ENOMEM 12
+#define EACCES 13
+#define EBADF 9
+#define EIO 5
+#define EEXIST 17
+#define ENOSYS 38
+
+#endif