Add missing initialization of a sigaction structure when I/O logging.

Fixes a potential problem when suspending the command.

src/exec_pty.c

@@ -334,6 +334,9 @@ suspend_parent(int signo)
 	}
 
 	/* Suspend self and continue child when we resume. */
+	zero_bytes(&sa, sizeof(sa));
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
 	sa.sa_handler = SIG_DFL;
 	sigaction(signo, &sa, &osa);
 	sudo_debug_printf(SUDO_DEBUG_INFO, "kill parent %d", signo);