pg_ctl: Disable autoruns for cmd.exe on Windows

On Windows, cmd.exe is used to launch the postmaster process to ease its
redirection setup.  However, cmd.exe may execute other programs at
startup due to autorun configurations, which could influence the
postmaster startup.  This patch adds /D flag to the launcher cmd.exe
command line to disable autorun settings written in the registry.

This is arguably a bug, but no backpatch is done now out of caution.

Reported-by: Hayato Kuroda
Author: Kyotaro Horiguchi
Reviewed-by: Robert Haas, Michael Paquier
Discussion: https://postgr.es/m/20230922.161551.320043332510268554.horikyota.ntt@gmail.com

Author: michaelpq

src/bin/pg_ctl/pg_ctl.c

@@ -552,11 +552,11 @@ start_postmaster(void)
 		else
 			close(fd);
 
-		cmd = psprintf("\"%s\" /C \"\"%s\" %s%s < \"%s\" >> \"%s\" 2>&1\"",
+		cmd = psprintf("\"%s\" /D /C \"\"%s\" %s%s < \"%s\" >> \"%s\" 2>&1\"",
 					   comspec, exec_path, pgdata_opt, post_opts, DEVNULL, log_file);
 	}
 	else
-		cmd = psprintf("\"%s\" /C \"\"%s\" %s%s < \"%s\" 2>&1\"",
+		cmd = psprintf("\"%s\" /D /C \"\"%s\" %s%s < \"%s\" 2>&1\"",
 					   comspec, exec_path, pgdata_opt, post_opts, DEVNULL);
 
 	if (!CreateRestrictedProcess(cmd, &pi, false))