diff -dur gcl-2.6.8.ORIG/o/unixfsys.c gcl-2.6.8/o/unixfsys.c
--- gcl-2.6.8.ORIG/o/unixfsys.c	2007-04-06 08:41:09.000000000 -0600
+++ gcl-2.6.8/o/unixfsys.c	2008-12-29 17:34:10.000000000 -0700
@@ -448,11 +448,17 @@
 backup_fopen(char *filename, char *option)
 {
 	char backupfilename[MAXPATHLEN];
+#ifndef HAVE_RENAME
 	char command[MAXPATHLEN * 2];
+#endif
 
 	strcat(strcpy(backupfilename, filename), ".BAK");
+#ifdef HAVE_RENAME
+	rename(filename, backupfilename);
+#else
 	sprintf(command, "mv %s %s", filename, backupfilename);
 	system(command);
+#endif
 	return(fopen(filename, option));
 }
 
@@ -477,6 +483,9 @@
 {
 	char filename[MAXPATHLEN];
 	char newfilename[MAXPATHLEN];
+#ifndef HAVE_RENAME
+	char command[MAXPATHLEN * 2];
+#endif
 
 	check_arg(2);
 	check_type_or_pathname_string_symbol_stream(&vs_base[0]);