signal的发送（暂时父子进程之间共享信号及相应的结构体） (#89)

* 解决由于spinlock.h中包含preempt_enable()带来的循环include问题

* new: 初步实现signal的数据结构

* new:signal相关数据结构

* fix: 解决bindings.rs报一堆警告的问题

* new: rust下的kdebug kinfo kwarn kBUG kerror宏

* 移动asm.h和cmpxchg.h

* new: signal的发送（暂时只支持父子进程共享信号及处理函数）

user/libs/libc/include/signal.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#define SIGHUP 1
+#define SIGINT 2
+#define SIGQUIT 3
+#define SIGILL 4
+#define SIGTRAP 5
+#define SIGABRT 6
+#define SIGIOT 6
+#define SIGBUS 7
+#define SIGFPE 8
+#define SIGKILL 9
+#define SIGUSR1 10
+#define SIGSEGV 11
+#define SIGUSR2 12
+#define SIGPIPE 13
+#define SIGALRM 14
+#define SIGTERM 15
+#define SIGSTKFLT 16
+#define SIGCHLD 17
+#define SIGCONT 18
+#define SIGSTOP 19
+#define SIGTSTP 20
+#define SIGTTIN 21
+#define SIGTTOU 22
+#define SIGURG 23
+#define SIGXCPU 24
+#define SIGXFSZ 25
+#define SIGVTALRM 26
+#define SIGPROF 27
+#define SIGWINCH 28
+#define SIGIO 29
+#define SIGPOLL SIGIO
+
+#define SIGPWR 30
+#define SIGSYS 31
+
+/* These should not be considered constants from userland.  */
+#define SIGRTMIN 32
+#define SIGRTMAX MAX_SIG_NUM