Move warn/error into common and make static builds work.

src/exec_pty.c

@@ -121,8 +121,8 @@ static void check_foreground(void);
 /*
  * Cleanup hook for error()/errorx()
  */
-void
-cleanup(int gotsignal)
+static void
+pty_cleanup(void)
 {
     debug_decl(cleanup, SUDO_DEBUG_EXEC);
 
@@ -1294,6 +1294,9 @@ exec_pty(struct command_details *details, int *errfd)
     pid_t self = getpid();
     debug_decl(exec_pty, SUDO_DEBUG_EXEC);
 
+    /* Register cleanup function */
+    error_callback_register(pty_cleanup);
+
     /* Set command process group here too to avoid a race. */
     setpgid(0, self);