--- gcl/o/run_process.c.orig	2020-01-31 11:48:18.373433926 -0700
+++ gcl/o/run_process.c	2020-01-31 11:54:22.417581265 -0700
@@ -540,10 +540,10 @@ char **argv;
   fdout = ostream->sm.sm_int;
   if (pfork() == 0)
     { /* the child --- replace standard in and out with descriptors given */
-      close(0);
-      massert(dup(fdin)>=0);
-      close(1);
-      massert(dup(fdout)>=0);
+      massert(dup2(fdin, 0)>=0);
+      massert(dup2(fdout, 1)>=0);
+      close(fdin);
+      close(fdout);
       emsg("\n***** Spawning process %s ", pname);
       if (execvp(pname, argv) == -1)
 	{