restart_syscall.2: SYNOPSIS: Fix restart_syscall() return type

The Linux kernel uses 'long' instead of 'int' for the return type.
As glibc provides no wrapper, use the same types the kernel uses.

$ grep -rn 'SYSCALL_DEFINE.*(restart_syscall'
kernel/signal.c:2891:SYSCALL_DEFINE0(restart_syscall)

$ sed -n 2891,2895p kernel/signal.c
SYSCALL_DEFINE0(restart_syscall)
{
	struct restart_block *restart = &current->restart_block;
	return restart->fn(restart);
}

$ grep -rn 'struct restart_block {'
include/linux/restart_block.h:25:struct restart_block {

$ sed -n 25,56p include/linux/restart_block.h
struct restart_block {
	long (*fn)(struct restart_block *);
	union {
		/* For futex_wait and futex_wait_requeue_pi */
		struct {
			u32 __user *uaddr;
			u32 val;
			u32 flags;
			u32 bitset;
			u64 time;
			u32 __user *uaddr2;
		} futex;
		/* For nanosleep */
		struct {
			clockid_t clockid;
			enum timespec_type type;
			union {
				struct __kernel_timespec __user *rmtp;
				struct old_timespec32 __user *compat_rmtp;
			};
			u64 expires;
		} nanosleep;
		/* For poll */
		struct {
			struct pollfd __user *ufds;
			int nfds;
			int has_timeout;
			unsigned long tv_sec;
			unsigned long tv_nsec;
		} poll;
	};
};

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/restart_syscall.2

@@ -34,7 +34,7 @@
 .SH NAME
 restart_syscall \- restart a system call after interruption by a stop signal
 .SH SYNOPSIS
-.B int restart_syscall(void);
+.B long restart_syscall(void);
 .PP
 .IR Note :
 There is no glibc wrapper for this system call; see NOTES.