renumber system calls

syscall.h

@@ -5,16 +5,16 @@
 #define SYS_write   5
 #define SYS_read    6
 #define SYS_close   7
-#define SYS_kill    9
-#define SYS_exec   10
-#define SYS_open   11
-#define SYS_mknod  12
-#define SYS_unlink 13
-#define SYS_fstat  14
-#define SYS_link   15
-#define SYS_mkdir  16
-#define SYS_chdir  17
-#define SYS_dup    18
-#define SYS_getpid 19
-#define SYS_sbrk   20
+#define SYS_kill    8
+#define SYS_exec    9
+#define SYS_open   10
+#define SYS_mknod  11
+#define SYS_unlink 12
+#define SYS_fstat  13
+#define SYS_link   14
+#define SYS_mkdir  15
+#define SYS_chdir  16
+#define SYS_dup    17
+#define SYS_getpid 18
+#define SYS_sbrk   19