Option stderr leaked a temporary FD into child process

CHANGES

@@ -37,6 +37,9 @@ Corrections:
 	The FDs of the socketpair that queues messages from signal handlers
 	lacked FD_CLOEXEC and thus leaked into EXEC and SYSTEM child processes.
 
+	Option stderr on addresses EXEC and SYSTEM uses a temporary FD. It
+	lacked the FD_CLOEXEC setting and thus leakt into child processes.
+
 Features:
 	VSOCK, VSOCK-L support options pf, socktype, prototype (currently
 	useless)

error.c

@@ -472,6 +472,7 @@ int diag_dup(void) {
       return -1;
    }
    newfd = dup(fileno(diagopts.logfile));
+   Fcntl_l(newfd, F_SETFD, FD_CLOEXEC);
    if (diagopts.logfile != stderr) {
       fclose(diagopts.logfile);
    }