syscalls needed for doom (tell/eof/draw_fb) + minor fixes, compiler shut up etc

docs/MANUAL.md

@@ -41,12 +41,4 @@ The recommended hardware to run PepperOS is the following:
 ## III. Syscall table
 
 The syscall interface in the Pepper kernel uses the System V ABI convention for argument order.
-It vaguely mimics Unix-like systems.
-
-Name | Number (%rax) | arg0 (%rdi) | arg1 (%rsi) | arg2 (%rdx) |
-|---|---|---|---|---|
-| sys_read | 0 | unsigned int fd | char* buf | size_t count |
-| sys_write | 1 | unsigned int fd | const char* buf | size_t count |
-| sys_open | 2 | const char* filename | int flags | |
-| sys_close | 3 | unsigned int fd | | |
-| sys_exit | 60 | int error_code | | |
+It vaguely mimics Unix-like systems. You will find it in [SYSCALLS.md](SYSCALLS.md).