[USER] brk syscall

libc/mem.c

@@ -0,0 +1,10 @@
+#include "syscalls.h"
+
+long kernel_syscall(int num, ...);
+
+SYSCALL_DEF(brk)
+{
+  SYSCALL_INIT(unsigned long, brk);
+
+  return kernel_syscall(SYS_BRK, brk);
+}

libc/syscall_num.h

@@ -1,4 +1,5 @@
 #pragma once
 
 #define SYS_WRITE 0x001
+#define SYS_BRK   0x002
 #define SYS_DEBUG 0x3FF