Declare syscall parsers using SYS_FUNC macro

Introduce SYS_FUNC macro to declare and define all syscall parsers.

* Makefile.am (BUILT_SOURCES, CLEANFILES): Add sys_func.h.
(sys_func.h): New rule.
* defs.h (SYS_FUNC_NAME, SYS_FUNC): New macros.
* linux/syscall.h: Include "sys_func.h".
[NEED_UID16_PARSERS]: Use SYS_FUNC to declare uid16 syscall parsers.
Remove other declarations.
* linux/alpha/syscallent.h (160, 161): Add sys_ prefix to osf_statfs
and osf_fstatfs syscall parsers.
* *.c: Use SYS_FUNC to define syscall parsers.
diff --git a/wait.c b/wait.c
index 08e3397..d2eb36d 100644
--- a/wait.c
+++ b/wait.c
@@ -139,21 +139,18 @@
 	return 0;
 }
 
-int
-sys_waitpid(struct tcb *tcp)
+SYS_FUNC(waitpid)
 {
 	return printwaitn(tcp, 3, 0);
 }
 
-int
-sys_wait4(struct tcb *tcp)
+SYS_FUNC(wait4)
 {
 	return printwaitn(tcp, 4, 0);
 }
 
 #ifdef ALPHA
-int
-sys_osf_wait4(struct tcb *tcp)
+SYS_FUNC(osf_wait4)
 {
 	return printwaitn(tcp, 4, 1);
 }
@@ -161,8 +158,7 @@
 
 #include "xlat/waitid_types.h"
 
-int
-sys_waitid(struct tcb *tcp)
+SYS_FUNC(waitid)
 {
 	if (entering(tcp)) {
 		printxval(waitid_types, tcp->u_arg[0], "P_???");