diff --git a/headers/posix/signal.h b/headers/posix/signal.h
index 28bc04aada..ad416775c7 100644
--- a/headers/posix/signal.h
+++ b/headers/posix/signal.h
@@ -12,25 +12,28 @@ extern "C" {
 #endif
 
 typedef int	sig_atomic_t;
+typedef void (*sig_func_t)(int);
+typedef void (*__signal_func_ptr)(int);  /* old BeOS typedef (kept for backwards compatibility) */
 
-typedef void (*__signal_func_ptr)(int);
 
-__signal_func_ptr signal(int signal, __signal_func_ptr signal_func);
-int raise(int  signal);
+sig_func_t signal(int sig, sig_func_t signal_handler);
+int        raise(int sig);
 
 #ifdef __cplusplus
 }
 #endif
 
-#define SIG_DFL	((__signal_func_ptr) 0)
-#define SIG_IGN	((__signal_func_ptr) 1)
-#define SIG_ERR	((__signal_func_ptr)-1)
+
+#define SIG_DFL	((sig_func_t) 0)
+#define SIG_IGN	((sig_func_t) 1)
+#define SIG_ERR	((sig_func_t)-1)
+
 
 /*
-   The numbering of signals for BeOS attempts to maintain 
-   some consistency with UN*X conventions so that things 
-   like "kill -9" do what you expect.
-*/   
+ * The numbering of signals for BeOS attempts to maintain 
+ * some consistency with UN*X conventions so that things 
+ * like "kill -9" do what you expect.
+ */   
 #define	SIGHUP      1      /* hangup -- tty is gone! */
 #define SIGINT      2      /* interrupt */
 #define SIGQUIT     3      /* `quit' special character typed in tty  */
@@ -56,11 +59,14 @@ int raise(int  signal);
 
 #define SIGBUS     SIGSEGV /* for old style code */
 
+
 /*
-   Signal numbers 23-32 are currently free but may be used in future
-   releases.  Use them at your own peril (if you do use them, at least
-   be smart and use them backwards from signal 32).
-*/
+ * Signal numbers 23-32 are currently free but may be used in future
+ * releases.  Use them at your own peril (if you do use them, at least
+ * be smart and use them backwards from signal 32).
+ */
+#define MAX_SIGNO 32
+
 #define __signal_max  22
 #define NSIG (__signal_max+1)
 
@@ -74,7 +80,7 @@ typedef long sigset_t;
    (the signal number) is passed to the signal handler.  It is useful
    to have more information and the BeOS provides two extra arguments.
    However, to remain compatible with Posix and ANSI C, we declare the
-   sa_handler field of the sigaction struct as type __signal_func_ptr.
+   sa_handler field of the sigaction struct as type 'sig_func_t'.
    That means you'll need to cast any function you assign to the
    sa_handler field.  NOTE: C++ member functions can not be signal
    handlers (because they expect a "this" pointer as the first
@@ -99,10 +105,10 @@ typedef long sigset_t;
 	  open some interesting programming possibilities.
 */
 struct sigaction {
-	__signal_func_ptr sa_handler;
-	sigset_t          sa_mask;
-	int               sa_flags;
-	void             *sa_userdata;  /* will be passed to the signal handler */
+	sig_func_t sa_handler;
+	sigset_t   sa_mask;
+	int        sa_flags;
+	void      *sa_userdata;  /* will be passed to the signal handler */
 };
 
 
@@ -124,41 +130,64 @@ typedef struct stack_t {
 extern "C" {
 #endif
 
+
 int sigaction(int sig, const struct sigaction *act, struct sigaction *oact);
+
 int sigemptyset(sigset_t *set);
 int sigfillset(sigset_t *set);
 int sigaddset(sigset_t *set, int signo);
 int sigdelset(sigset_t *set, int signo);
 int sigismember(const sigset_t *set, int signo);
 int sigprocmask(int how, const sigset_t *set, sigset_t *oset);
+
 extern const char * const sys_siglist[NSIG];
 const char *strsignal(int sig);
+
 const void  set_signal_stack(void *ptr, size_t size);
 int sigaltstack(const stack_t *ss, stack_t *oss);         /* XXXdbg */
 
+
+extern inline int
+sigemptyset(sigset_t *set)	
+{
+	*set = (sigset_t) 0L;
+	return 0;
+}
+
+extern inline int
+sigfillset(sigset_t *set)
+{
+	*set = (sigset_t) ~(0UL);
+	return 0;
+}
+
 extern inline int
 sigismember(const sigset_t *set, int sig)	
-{	
+{
 	sigset_t mask = (((sigset_t) 1) << (( sig ) - 1)) ;	
 	return   (*set & mask) ? 1 : 0 ;	
-} 
+}
+
 extern inline int
 sigaddset(sigset_t *set, int sig)	
-{	
+{
 	sigset_t mask = (((sigset_t) 1) << (( sig ) - 1)) ;	
 	return   ((*set |= mask), 0) ;	
-} 
+}
+
 extern inline int
 sigdelset(sigset_t *set, int sig)	
-{	
+{
 	sigset_t mask = (((sigset_t) 1) << (( sig ) - 1)) ;	
 	return   ((*set &= ~mask), 0) ;	
 } 
 
+
 #define SIG_BLOCK    1   /* defines for the how arg of sigprocmask() */
 #define SIG_UNBLOCK  2
 #define SIG_SETMASK  3
 
+
 int sigpending(sigset_t *set);
 int sigsuspend(const sigset_t *mask);
 
@@ -169,7 +198,9 @@ int send_signal(pid_t tid, uint sig);
 }
 #endif
 
+
 /* signal handlers get this as the last argument */
+
 typedef struct vregs vregs;
 
 #if __POWERPC__